Answer:
Explanation:
Two constitutional isomers of C₂H₇P
1 ) CH₃-CH₂ - PH₂ ( Ethyl phosphane )
2 ) CH₃ - PH - CH₃ ( Dimethyl phosohane )
The chemical formulae of constitutional isomers are the same, but their connectivities differ. Constitutional isomers include ethanol and dimethyl ether, as well as n-butane and isobutane.
Although structural (constitutional) isomers share the same chemical formula, their atoms are bonded in different ways. Stereoisomers share the same atomic configurations and chemical formulae. Only the spatial arrangement of the groups within the molecule separates them from one another.
Compounds with the same chemical formula but different properties are known as isomers. Constitutional isomers are isomers that have different atom connections.
Two constitutional isomers of C₂H₇P
1 ) CH₃-CH₂ - PH₂ ( Ethyl phosphane )
2 ) CH₃ - PH - CH₃ ( Dimethyl phosphane )
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A sample of sulfur weighing 0.210 g was dissolved in 17.8 g of carbon disulfide, CS₂ (Kb = 2.43 °C/m).
If the boiling point elevation was 0.107 °C, what is the formula of a sulfur molecule in carbon disulfide?
Answer : The formula of a sulfur molecule in carbon disulfide is, [tex]S_8[/tex]
Explanation :
Formula used for Elevation in boiling point :
[tex]\Delta T_b=i\times k_b\times m[/tex]
or,
[tex]\Delta T_b=i\times k_b\times \frac{w_2\times 1000}{M_2\times w_1}[/tex]
where,
[tex]\Delta T_b[/tex] = boiling point of elevation = [tex]0.107^oC[/tex]
[tex]k_b[/tex] = boiling point constant of carbon disulfide = [tex]2.43^oC/m[/tex]
m = molality
i = Van't Hoff factor = 1 (for non-electrolyte
[tex]w_2[/tex] = mass of solute (sulfur sample) = 0.210 g
[tex]w_1[/tex] = mass of solvent (carbon disulfide) = 17.8 g
[tex]M_2[/tex] = molar mass of solute (sulfur sample) = ?
Now put all the given values in the above formula, we get:
[tex]0.107^oC=1\times (2.43^oC/m)\times \frac{(0.210g)\times 1000}{M_2\times (17.8g)}[/tex]
[tex]M_2=267.93g/mol[/tex]
The molar mass of sulfur sample is, 267.93 g/mol
Now we have to determine the formula of a sulfur molecule in carbon disulfide.
Let the compound of sulfur be, [tex]S_n[/tex]
Molar mass of [tex]S_n[/tex] = n × Molar mass of S
267.93 g/mol = n × 32 g/mol
n = 8
Thus, the formula of a sulfur molecule in carbon disulfide is, [tex]S_8[/tex]
In addition to continuous radiation, fluorescent lamps emit sharp lines in the visible region from a mercury discharge within the tube. Much of this light has a wavelength of 436 nm. What is the energy (in J) of one photon of this light?
Answer:
[tex]4.56 x 10^{-19}J[/tex]
Explanation:
Electromagnetic radiations consist of quanta of energy called photons which have energy, E which is equal to:
E = hν.....................................(1)
where h is the Planck's constant which is [tex]6.626 x10^{-34}Js[/tex] and ν is the frequency of light radiation.
But ν = c/λ ....................................(2)
Putting equation (2) into (1), we have
E = hc/λ..........................................(3)
c is the speed of light (c =[tex]3 x 10^{8}m/s[/tex]) while λ is the wavelength of light.
Wavelength λ = 436nm = [tex]436 x 10^{-9}m[/tex]
Therefore the energy E of one photon of this light, using equation (3) is
[tex]E=\frac{6.626 x 10^{-34} x3 x10^{8} }{436 x 10^{-9} } = 4.56 x 10^{-19} J[/tex]
The energy of one photon of light with a wavelength of 436 nm is 4.546 × 10^-19 J.
Explanation:To calculate the energy of one photon, we can use the equation E = hc/λ, where E is the energy, h is Planck's constant (6.626 × 10-34 J·s), c is the speed of light (3.00 × 108 m/s), and λ is the wavelength.
Plugging in the given wavelength of 436 nm (which is equal to 4.36 × 10-7 m) into the equation, we have:
E = (6.626 × 10-34 J·s)(3.00 × 108 m/s) / (4.36 × 10-7 m) = 4.546 × 10-19 J
Therefore, the energy of one photon of light with a wavelength of 436 nm is 4.546 × 10-19 J.
In a reaction, gaseous reactants form a liquid product. The heat absorbed by the surroundings is 1.1 MJ, and the work done on the system is 13.2 kcal. Calculate ΔE (in kJ). Be sure to include the correct sign (+/-). Enter to 0 decimal places.
The change in energy of the system in the given reaction is -1045 kJ. This value is calculated using the first law of thermodynamics taking in account that the energy absorbed is lost by the system and the work done on the system is obtained.
Explanation:In this chemical reaction, we are dealing with a process that involves heat absorption and work done on the system. Both these elements contribute to the change in energy of the system, denoted by ΔE.
The first law of thermodynamics states that ΔE = q + w, where 'q' represents heat and 'w' represents work. However, notice that the heat is absorbed by the surroundings, which means the system is losing that amount of heat, so q = -1.1 MJ = -1100 kJ (as 1MJ = 1000 kJ).
Also, the work is done on the system, so it's positive, and it's given in calories, we need to convert it into kilojoules (kJ), for that, use the conversion factor 1 cal= 0.004184 kJ, so w = 13.2 kcal * 4.184 = 55.23 kJ.
Plugging these values into thermodynamics equation, we get ΔE = -1100 kJ + 55.23 kJ = -1044.77 kJ. Thus, the change in energy of the system, ΔE, is -1045 kJ (rounded to 0 decimal places).
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Final answer:
To calculate the change in internal energy (ΔE) for the reaction, convert all values to kJ, then apply the formula ΔE = q + w. The answer is +1155 kJ, indicating energy absorption.
Explanation:
The question asks to calculate the change in internal energy (ΔE) for a chemical reaction where gaseous reactants form a liquid product. The energy absorbed by the surroundings is given as 1.1 MJ, and the work done on the system is 13.2 kcal. To find ΔE, we use the formula ΔE = q + w, where q is the heat absorbed by the system and w is the work done on the system.
First, convert all values to the same unit (kJ): Heat absorbed, q = 1.1 MJ = 1100 kJ; Work done, w = 13.2 kcal × 4.184 kJ/kcal = 55.23 kJ. Thus, ΔE = 1100 kJ + 55.23 kJ = 1155.23 kJ. Therefore, the change in internal energy for the reaction is +1155 kJ, indicating that the system absorbed energy.
Wastewater from a cement factory contains 0.280 g of Ca2 ion and 0.0550 g of Mg2 ion per 100.0 L of solution. The solution density is 1.001 g/mL. Calculate the Ca2 and Mg2 concentrations in ppm (by mass).
Answer:
The correct answer is: 2.8 ppm Ca²⁺ and 0.55 ppm Mg²⁺
Explanation:
ppm (by mass) is equal to: mass solute (mg)/mass solution(kg)
First, we use the solution density to calculate the mass of 100.0 L solution in kg:
mass solution= 100.0 L x 1.001 g/ml x 1000 ml/ 1L x 1kg/1000 g= 100.1 kg
Then, we divide the mass of each ion (in mg) into the mass solution to obtain the ppm:
mg Ca²⁺= 0.280 g x 1000 mg/1g= 280 mg
mg Mg²⁺= 0.0550 g x 1000 mg/1g= 55 mg
ppm Ca²⁺= 280 mg Ca²⁺/ 100.1 kg solution= 2.797 mg Ca²⁺/kg solution= 2.8 ppm
ppm Mg²⁺= 55 mg Mg²⁺/ 100.1 kg solution= 0.549 mg Mg²⁺/kg solution= 0.55 ppm
What is the total probability of finding a particle in a one-dimensional box in level n = 4 between x = 0 and x = L/8?
Answer:
P = 1/8
Explanation:
The wave function of a particle in a one-dimensional box is given by:
[tex] \psi = \sqrt \frac{2}{L} sin(\frac{n \pi x}{L}) [/tex]
Hence, the probability of finding the particle in the one-dimensional box is:
[tex] P = \int_{x_{1}}^{x_{2}} \psi^{2} dx [/tex]
[tex] P = \int_{x_{1}}^{x_{2}} (\sqrt \frac{2}{L} sin(\frac{n \pi x}{L}))^{2} dx [/tex]
[tex] P = \frac{2}{L} \int_{x_{1}}^{x_{2}} (sin^{2}(\frac{n \pi x}{L}) dx [/tex]
Evaluating the above integral from x₁ = 0 to x₂ = L/8 and solving it, we have:
[tex] P = \frac{2}{L} [\frac{L}{16} (1 - 4\frac{sin(\frac{n \pi}{4})}{n \pi})] [/tex]
[tex] P = \frac{1}{8} (1 - 4\frac{sin(\frac{n \pi}{4})}{n \pi}) [/tex]
Solving for n=4:
[tex] P = \frac{1}{8} (1 - 4\frac{sin(\frac{4 \pi}{4})}{4 \pi}) [/tex]
[tex] P = \frac{1}{8} (1 - \frac{sin (\pi)}{\pi}) [/tex]
[tex] P = \frac{1}{8} [/tex]
I hope it helps you!
The total probability of finding a particle in this one-dimensional box is [tex]\frac{1}{8}[/tex]
Given the following data:
Energy level, n = 4x = 0x = [tex]\frac{L}{8}[/tex]To determine the total probability of finding a particle in a one-dimensional box:
A particle in a one-dimensional box describes the translational motion of a particle that is trapped inside an infinitely deep well, from which it is unable to escape.
Mathematically, the wave function of a particle in a one-dimensional box is given by this formula:
[tex]\psi = \sqrt{\frac{2}{L} } sin\frac{n\pi}{L} x[/tex] ...equation 1.
Where:
[tex]\psi[/tex] is the wave function.L is the length of a box.x is the displacement.In a one-dimensional box, the probability of finding a particle is given by the formula:
[tex]P=\int\limits^{x_2}_{x_1} {\psi^2} \, dx[/tex] ...equation 2.
Substituting eqn. 1 into eqn. 2, we have:
[tex]P=\int\limits^{x_2}_{x_1} {(\sqrt{\frac{2}{L} } sin\frac{n\pi}{L} x)^2} \, dx \\\\P = \frac{2}{L} \int\limits^{x_2}_{x_1} {( sin^2(\frac{n\pi}{L} x))} \, dx\\\\P=\frac{2}{L} [\frac{L}{16} (1-4(\frac{sin\frac{n\pi}{4} }{n\pi} ))]\\\\P=\frac{1}{8} (1-4(\frac{sin\frac{n\pi}{4} }{n\pi} ))[/tex]
Substituting the value of n, we have:
[tex]P=\frac{1}{8} (1-4(\frac{sin\frac{4\pi}{4} }{4\pi} ))\\\\P=\frac{1}{8} (1-(\frac{sin\pi }{\pi} ))\\\\P=\frac{1}{8} (1-0)\\\\P=\frac{1}{8}[/tex]
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One bit of evidence that the quantum mechanical model is "correct" lies in the magnetic properties of matter. Atoms with unpaired electrons are attracted by magnetic fields and thus are said to exhibit paramagnetism. The degree to which this effect is observed is directly related to the number of unpaired electrons present in the atom. Consider the ground-state electron configuration for . Would this atom be expected to be paramagnetic, and how many unpaired electrons are present? It has unpaired electron(s). Consider the ground-state electron configuration for . Would this atom be expected to be paramagnetic, and how many unpaired electrons are present?
Answer:
Li, N, Ni, Te
Explanation:
First let us consider the number of unpaired electrons in each of the given atoms.
Li-1
N-3
Ni-2
Te-2
For an atom to be paramagnetic, it must possess at least one unpaired electron in its valence shell. Ba and Hg are not paramagnetic because all electrons in their outermost shells are spin paired.
The more the number of unpaired electrons in the outermost shell of an atom, the greater its paramagnetic behavior.
Whether an atom is paramagnetic depends on the presence of unpaired electrons in its ground state electron configuration. The number of unpaired electrons determines the strength of its paramagnetism. For example, a nitrogen atom has three unpaired electrons leading it to exhibit paramagnetism.
Explanation:The question has asked about the paramagnetism and unpaired electrons present in an atom according to the quantum mechanical model. However, the specific atom is not given in the question. In general, if an atom has unpaired electrons in its ground state electron configuration, it will exhibit paramagnetic behavior. The number of unpaired electrons will determine the strength of this effect.
For example, let's consider an atom of nitrogen. According to quantum mechanics, a nitrogen atom has 7 electrons. In its ground state, it has two electrons in 1s orbital, two in 2s, and three in 2p orbitals. Only the three 2p electrons are unpaired. Therefore, a nitrogen atom exhibits paramagnetism due to these three unpaired electrons.
Likewise, you can determine the magnetic properties of any atom by examining its electron configuration and identifying the number of unpaired electrons.
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When glucose goes from an open-chain form [Image 1] to a cyclic form [Image 2] in solution, it loses one type of functional group and gains another type of functional group. Which choice below corresponds to the functional groups unique to the open-chain and cyclic forms, respectively?
ketone; secondary alcohol
aldehyde; epoxide
primary alcohol; epoxide
aldehyde; ether
ketone; ether
The aldehyde group changes to ether group.
Explanation:In the straight chain glucose molecule, there's the 6 carbon atoms attached with each other where there are several hydrogen and hydroxyl radicals attached. The C1 of glucose contains the aldehyde group and the C5 is the most reactive atom of glucose. In a solution, the lone pair of the oxygen atom of hydroxyl group of C5 attacks the electrophilic centre of C1, forming a carbon oxygen ether bond. This bond makes the double bonded oxygen weaker and one of the bond breaks forming oxygen radicle, which then attracts the hydrogen radicle emitted by the ether oxygen to form a hydroxyl group. This is how the ring structure forms in a solution.
Thus, the aldehyde group of glucose changes to ether group.
Fluorine-18 is a radioactive isotope that decays by positron emission to form oxygen-18 with a half-life of 109.8 min. (A positron is a particle with the mass of an electron and a single unit of positive charge.) What is the rate constant (in min−1) for the decomposition of fluorine-18?
Answer:
k = 6.31 x 10⁻³ min⁻¹
Explanation:
The equation required to solve this question is:
k = 0693 / t half-life
This equation is derived from the the equation from the radioctive first order reactions:
ln At/A₀ = -kt
where At is the number of isoopes after a time t , and A₀ is the number of of isotopes initially. The half-life is when the number of isotopes has decayed by a half, so
ln(1/2) = -kt half-life
-0.693 = - k t half-life
t half-life = 109.8 min
⇒ k = 0.693 / t half-life = 0.693 / 109.8 min = 6.31 x 10⁻³ min⁻¹
The rate constant for the decomposition of Fluorine-18 is 0.00631 min⁻¹, calculated using the formula k = 0.693 / t₁/₂ where the half-life t₁/₂ is 109.7 minutes.
Explanation:Radioactive Decay of Fluorine-18The decay of Fluorine-18 (¹8F) is described by first-order kinetics, which means the rate of decay is proportional to the amount of ¹8F present. The half-life of ¹8F is given as 109.7 minutes. To determine the rate constant (k) for the decomposition of Fluorine-18, we use the relationship between the half-life (t1/2) and rate constant for first-order reactions: k = 0.693 / t1/2. Substituting the given half-life into this equation, we get:
k = 0.693 / 109.7 min = 0.00631 min-1
This is the rate constant for the decomposition of Fluorine-18.
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You are presented with a mystery as part of your practical experiment. You have a solution of Pb(NO3)2 that has a worn label making it impossible to read. You know the concentration is below 1.0 M as you can make out "0.xxx" at the beginning of the label. In order to determine the concentration, you decide to precipitate out the lead in the solution as PbSO4.
If you added 1.0 mL of the unknown Pb(NO3)2 to a test tube, what is the amount of H2SO4 in mL you will need to add to be sure the H2SO4 is the excess reagent?
Answer:
Minimum volume of H₂SO₄ required for H₂SO₄ to be in excess = 0.0556 mL
Explanation:
Pb(NO₃)₂ + H₂SO₄ -----> PbSO₄ + 2HNO₃
For this reaction, we know that the max concentration of Pb(NO₃) according to the bottle is 0.999M and to ensure the other reactant in the reaction is in excess, we'll do the calculation with a Pb(NO₃) that's a bit higher, that is, 1.0M.
Knowing that Concentration in mol/L = (number of moles)/(volume in L)
Number of moles of Pb(NO₃) added = concentration in mol/L × volume in L = 1 × 0.001 = 0.001 mole
According to the reaction,
1 mole of Pb(NO₃) reacts with 1 mole of H₂SO₄
0.001 mole of Pb(NO₃) will react with 0.001×1/1 mole of H₂SO₄
Therefore number of H₂SO₄ required for the reaction and for the H₂SO₄ to be in excess is 0.001 mole of H₂SO₄
So, the concentration of commercial H₂SO₄ is usually 18.0M, using this as the assumed value.
Volume of H₂SO₄ = (number of H₂SO₄ required for it to be in excess)/(concentration of H₂SO₄)
Volume of H₂SO₄ = 0.001/18 = 0.0000556 L = 0.0556 mL.
QED!!!
Assuming concentrated H₂SO₄ is used for the precipitation, the minimum volume of concentrated H₂SO₄ required to be the excess reagent is 0.0556 mL.
What volume of H₂SO₄ is required for H₂SO₄ to be in excessThe equation of the reaction between H₂SO₄ and Pb(NO₃)₂ is given below:
Pb(NO₃)₂ + H₂SO₄ -----> PbSO₄ + 2HNO₃Assuming that the concentration of Pb(NO₃)₂ is 1.0M.
Number of moles of Pb(NO₃)₂ in 1.0 mL solution is calculated as follows:
Number of moles = molarity * volume in LVolume of Pb(NO₃)₂ = 1.0 mL = 0.001 L
Number of moles of Pb(NO₃)₂ = 1.0 * 0.001
Number of moles of Pb(NO₃)₂ = 0.001 moles
From the equation of reaction:
1 mole of Pb(NO₃)₂ reacts with 1 mole of H₂SO₄
0.001 mole of Pb(NO₃)₂ will react with 0.001 moles of H₂SO₄
Therefore number of moles H₂SO₄ required for the reaction and for the H₂SO₄ to be in excess is 0.001 mole of H₂SO₄
Assuming the H₂SO₄ required is concentrated H₂SO₄:
Concentration of concentrated H₂SO₄ = 18.0M
The volume of concentrated H₂SO₄ required is calculated as follows:
Volume = moles/molarityVolume of H₂SO₄ = 0.001/18
Volume of H₂SO₄ = 0.0000556 L
Volume of concentrated H₂SO₄ required = 0.0556 mL.
Therefore, the minimum volume of concentrated H₂SO₄ required to be the excess reagent is 0.0556 mL.
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What happens to the volume of a gas when you double the number of moles of gas while keeping the temperature and pressure constant?
Answer: The volume of the gas also gets double when number of moles are doubled.
Explanation:
The relationship of number of moles and volume at constant temperature and pressure was given by Avogadro's law. This law states that volume is directly proportional to number of moles at constant temperature and pressure.
The equation used to calculate number of moles is given by:
[tex]\frac{V_1}{n_1}=\frac{V_2}{n_2}[/tex]
where,
[tex]V_1\text{ and }n_1[/tex] are the initial volume and number of moles
[tex]V_2\text{ and }n_2[/tex] are the final volume and number of moles
We are given:
[tex]n_2=2n_1[/tex]
Putting values in above equation, we get:
[tex]\frac{V_1}{n_1}=\frac{V_2}{2n_1}\\\\V_2=\frac{2n_2\times V_1}{n_1}=2V_2[/tex]
Hence, the volume of the gas also gets double when number of moles are doubled.
Final answer:
Doubling the number of moles of a gas while keeping temperature and pressure constant will double the volume of the gas, in accordance with Avogadro's law.
Explanation:
When we double the number of moles of gas while keeping the temperature and pressure constant, according to Avogadro's law, the volume of the gas also doubles. This is because Avogadro's law states that at constant temperature and pressure, the volume of a gas is directly proportional to the number of moles of the gas. Therefore, if the amount of gas is doubled, the volume also doubles, assuming the gas behaves ideally.
Technetium (Tc; Z = 43) is a synthetic element used as a radioactive tracer in medical studies. A Tc atom emits a beta particle (electron) with a kinetic energy (Ek) of 4.71 x 10¹⁵ J. What is the de Broglie wavelength of this electron (Ek = ½mv²)?
Question in incomplete, complete question is:
Technetium (Tc; Z = 43) is a synthetic element used as a radioactive tracer in medical studies. A Tc atom emits a beta particle (electron) with a kinetic energy (Ek) of [tex]4.71\times 10^{-15}J[/tex] . What is the de Broglie wavelength of this electron (Ek = ½mv²)?
Answer:
[tex] 6.762\times 10^{-12} m[/tex] is the de Broglie wavelength of this electron.
Explanation:
To calculate the wavelength of a particle, we use the equation given by De-Broglie's wavelength, which is:
[tex]\lambda=\frac{h}{\sqrt{2mE_k}}[/tex]
where,
= De-Broglie's wavelength = ?
h = Planck's constant = [tex]6.624\times 10^{-34}Js[/tex]
m = mass of beta particle = [tex] 9.1094\times 10^{-31} kg[/tex]
[tex]E_k[/tex] = kinetic energy of the particle = [tex]4.71\times 10^{-15}J[/tex]
Putting values in above equation, we get:
[tex]\lambda =\frac{6.624\times 10^{-34}Js}{\sqrt{2\times 9.1094\times 10^{-31} kg\times 4.71\times 10^{-15}J}}[/tex]
[tex]\lambda = 6.762\times 10^{-12} m[/tex]
[tex] 6.762\times 10^{-12} m[/tex] is the de Broglie wavelength of this electron.
Finally, sometimes the desired value does not directly match the units given but is derived from the calculation required. For example, a sheet of metal that has a volume of 45.5 cm3 has a width of 14.8 cm and has a length 15.9 cm. What is the thickness (that is, the height) of the metal sheet in millimeters?
Answer: The thickness of metal sheet is 1.93 mm
Explanation:
The metals sheet is in the form of cuboid.
To calculate the width of the metal sheet for the given volume, we use the equation to calculate the volume of cuboid, which is:
[tex]V=lbh[/tex]
where,
V = volume of metal sheet = [tex]45.5cm^3[/tex]
l = length of metal sheet = 15.9 cm
b = width of metal sheet = 14.8 cm
h = height of metal sheet = ? cm
Putting values in above equation, we get:
[tex]45.5cm^3=15.9\times 14.8\times h\\\\h=\frac{45.5}{15.9\times 14.8}=0.193cm[/tex]
Converting this thickness into millimeters, we use the conversion factor:
1 cm = 10 mm
So, [tex]0.193cm\times \frac{10mm}{1cm}=1.93mm[/tex]
Hence, the thickness of metal sheet is 1.93 mm
To find the thickness (height) of the metal sheet, use the formula for volume and rearrange it to solve for the height.
To find the thickness (height) of the metal sheet, we can use the formula for volume. The formula for volume of a rectangular solid is:
Volume = Length * Width * Height
Given that the volume is 45.5 cm3, the length is 15.9 cm, and the width is 14.8 cm, we can rearrange the formula to solve for the height:
Height = Volume / (Length * Width)
Substituting the values, we have:
Height = 45.5 cm3 / (15.9 cm * 14.8 cm)
We can now calculate the height of the metal sheet in millimeters.
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In compliance with conservation of energy, Einstein explained that in the photoelectric effect, the energy of a photon (hv) absorbed by a metal is the sum of the work function (Φ), the minimum energy needed to dislodge an electron from the metal’s surface, and the kinetic energy (Ek) of the electron: hv = Φ + Ek. When light of wavelength 358.1 nm falls on the surface of potassium metal, the speed (u) of the dislodged electron is 6.40 x 10⁵ m7s. (a) What is Ek (½mu²) of the dislodged electron? (b) What is Φ (in J) of potassium?
Answer:
a) 1.866 × 10 ⁻¹⁹ J b) 3.685 × 10⁻¹⁹ J
Explanation:
the constants involved are
h ( Planck constant) = 6.626 × 10⁻³⁴ m² kg/s
Me of electron = 9.109 × 10 ⁻³¹ kg
speed of light = 3.0 × 10 ⁸ m/s
a) the Ek ( kinetic energy of the dislodged electron) = 0.5 mu²
Ek = 0.5 × 9.109 × 10⁻³¹ × ( 6.40 × 10⁵ )² = 1.866 × 10 ⁻¹⁹ J
b) Φ ( minimum energy needed to dislodge the electron ) can be calculated by this formula
hv = Φ + Ek
where Ek = 1.866 × 10 ⁻¹⁹ J
v ( threshold frequency ) = c / λ where c is the speed of light and λ is the wavelength of light = 358.1 nm = 3.581 × 10⁻⁷ m
v = ( 3.0 × 10 ⁸ m/s ) / (3.581 × 10⁻⁷ m ) = 8.378 × 10¹⁴ s⁻¹
hv = 6.626 × 10⁻³⁴ m² kg/s × 8.378 × 10¹⁴ s⁻¹ = 5.551 × 10⁻¹⁹ J
5.551 × 10⁻¹⁹ J = 1.866 × 10 ⁻¹⁹ J + Φ
Φ = 5.551 × 10⁻¹⁹ J - 1.866 × 10 ⁻¹⁹ J = 3.685 × 10⁻¹⁹ J
A 50.0 mL sample of waste process water from a food processing plant weighing 50.1 g was placed in a properly prepared crucible that had a tare weight of 17.1234 g. After drying in a 103oC oven it weighed 19.9821 g. After the crucible was placed in a 550oC oven it weighted 18.7777 g. What are the TS and VS (in mg/L)?
Answer:
TS (total solid, mg/L) = 57,174 mg/L
VS (volatile solid, mg/L) = 24,088 mg/L
Explanation:
First step to solve this problem is to know data and questions:
Data:
Sample volume = 50 mL
Sample weight = 50.1 g
P1 (weight empty crucible) = 17.1234 g
P2 (weight after drying a 103º in oven) = 19.9821 g
P3 (weight after incinatrion 550º) = 18.7777 g
Questions:
TS = ?
VS = ?
Formula:
We need to use formulas to calculate total solid (TS) and volatile solid (VS), these are:
[tex]TS =\frac{(P2-P1)*\frac{1,000 mg}{1g} }{Sample volumen (L)}[/tex]
[tex]VS = \frac{(P2-P3)*\frac{1,000 mg}{1g} }{Sample volume (L)}[/tex]
We have to transform mL to L so we will divide mL by 1,000 the sample volume:
[tex]Sample Volumen (L) = 50 mL * \frac{1L}{1,000 mL} = 0.05 L[/tex]
In the formula the value of 1,000 results by the convertion factor to transform grams to miligrams (we have to multiplie by 1,000)
Now we need to replace data on previous formulas and we will get TS and VS expressed in mg/L:
[tex]TS = \frac{(19.9821 g-17.1234g)*\frac{1,000 mg}{1g} }{0.05L} = 57,174mg/L[/tex]
[tex]VS = \frac{(19.9821g-18.7777g)*\frac{1,000mg}{1g} }{0.05L}=24,088 mg/L[/tex]
We divide TS and VS formula by sample volume because the exercise is asking us to express the results in mg/L.
If the value of n = 2
... The quantum number l can have values from
to .
... The total number of orbitals possible at the n = 2 energy level is .
If the value of l = 3
... The quantum number ml can have values from to .
... The total number of orbitals possible at the l = 3 sublevel is
Quantum numbers n, l, and ml are used to describe an electron's location in an atom. For n=2, l can be 0 or 1, and four orbitals exist. For l=3, ml can range from -3 to 3, providing seven orbitals.
Explanation:
In the realm of quantum mechanics, the values of the quantum numbers n, l, and ml tell us a lot about the electron's location in an atom. If the principal quantum number, n = 2, the angular momentum quantum number, l, can have values ranging from 0 to n-1. In this case, that means l can be 0 or 1. With this, the total number of orbitals (regions where you can most likely find an electron) possible at the n = 2 energy level is 4 (calculated as n2).
If the magnetic quantum number, l = 3, then, the magnetic quantum number ml can have values ranging from -l to +l, which means ml can range from -3 to 3. This produces a total of 7 orbitals possible at the l = 3 sublevel, each of which can hold two electrons.
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For n = 2, l can have values 0 and 1, with a total of 4 orbitals. For l = 3, ml ranges from -3 to 3, with 7 orbitals at the l = 3 sublevel.
The problem involves determining the possible values of different quantum numbers. When the principal quantum number n is 2, the angular momentum quantum number l can range from 0 to n-1, meaning l can have the values 0 and 1. The total number of orbitals possible at the n = 2 energy level is calculated by the formula n², thus the number is 4 orbitals.
If the angular momentum quantum number l is 3, the magnetic quantum number ml can range from -l to +l, meaning it can have values from -3 to 3 (-3, -2, -1, 0, 1, 2, 3). The total number of orbitals possible at the l = 3 sublevel is 2l+1, which is 7.
Which element would you expect to be more metallic?
(a) Ca or Rb (b) Mg or Ra (c) Br or I
Explanation:
When we move across a period from left to right then there will occur an increase in electronegativity and also there will occur an increase in non-metallic character of the elements.
As calcium (Ca) is a group 2A element and rubidium (Rb) is a group 1A element. Hence, Rb being an alkali metal is more metallic in nature than calcium (alkaline earth metal).
Both magnesium (Mg) and radium (Ra) are group 2A elements. And, when we move down a group then as the size of element increases so, it becomes easy of the metal atom to lose an electron.
As a result, there occurs an increase in metallic character of the element. Hence, Radium (Ra) is more metallic in nature than magnesium (Mg).
Also, both bromine and iodine are group 17 elements. Since, both of them are non-metals and non-metallic character increases on moving down the group.
Therefore, bromine (Br) is more metallic than iodine.
In the context of the periodic table, metallicity increases further down a group and decreases from left to right across a period. Therefore, Rb, Ra, and I are expected to be more metallic than Ca, Mg, and Br respectively.
Explanation:In an element, the metallicity increases as we go down a group (or column) on the periodic table, and decreases as we move from left to right across a period (or row). Therefore, based on the periodic table:
Rb (Rubidium) would likely be more metallic than Ca (Calcium) because it is located further down the same group.Ra (Radium) would be more metallic than Mg (Magnesium) for the same reason, it is situated further down the same group.I (Iodine) would likely be more metallic than Br (Bromine) because it is also located further down the same group.Learn more about Metallicity here:https://brainly.com/question/28650063
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Calculate the molality of a solution containing 100.7 g of glycine (NH2CH2COOH) dissolved in 3.466 kg of H2O.
Answer : The molality of a solution is, 0.387 mol/kg
Explanation : Given,
Mass of solute (glycine) = 100.7 g
Mass of solvent (water) = 3.466 kg
Molar mass of glycine = 75.1 g/mole
Formula used :
[tex]Molality=\frac{\text{Mass of solute}}{\text{Molar mass of solute}\times \text{Mass of solvent}}[/tex]
Now put all the given values in this formula, we get:
[tex]Molality=\frac{100.7g}{75.1g/mol\times 3.466kg}[/tex]
[tex]Molality=0.387mol/kg[/tex]
Thus, the molality of a solution is, 0.387 mol/kg
Answer:
The molality of the solution is 0.387 molal
Explanation:
Step 1: Data given
Mass of glycine = 100.7 grams
Mass of H2O = 3.466 kg
Molar mass of glycine = 75.07 g/mol
Step 2: Calculate moles glycine
Moles glycine = mass glycine / molar mass glycine
Moles glycine = 100.7 grams / 75.07 g/mol
Moles glycine = 1.341 moles
Step 3: Calculate molality of the solution
Molality = moles glycine / mass H2O
Molality = 1.341 moles / 3.466 kg
Molality = 0.387 molal
The molality of the solution is 0.387 molal
A solution was prepared by dissolving 28.0g of KCL in 225g of water. Part A Calculate the mass percent ofKCL in the solution. Part B Calculate the mole fraction of KCL in the solution. Express the concentration numerically as a mole fraction in decimal form. Part C Calculate the molarity of in the solution if the total volume of the solution is 239 . Express your answer with the appropriate units. Part D Calculate the molality of KCL in the solution. Express your answer with the appropriate units.
Answer:
A. 11.1%
B. 0.0291
C. 1.57 M
D. 1.67 m
Explanation:
A.
Mass of KCl (solute): 28.0 g
Mass of water (solvent): 225 g
Mass of solution: 28.0 g + 225 g = 253 g
The mass percent of KCl is:
%KCl = (mass of KCl/mass of solution) × 100%
%KCl = (28.0 g/253 g) × 100%
%KCl = 11.1%
B.
The molar mass of KCl is 74.55 g/mol. The moles of KCl are:
28.0 g × (1 mol/74.55 g) = 0.376 mol
The molar mass of water is 18.02 g/mol. The moles of water are:
225 g × (1 mol/18.02 g) = 12.5 mol
The total number of moles is 0.376 mol + 12.5 mol = 12.9 mol.
The mole fraction of KCl is:
X(KCl) = moles of KCl / total moles
X(KCl) = 0.376 mol / 12.9 mol
X(KCl) = 0.0291
C.
The volume of the solution is 239 mL (0.239 L).
The molarity of KCl is:
M = moles of KCl / liters of solution
M = 0.376 mol / 0.239 L
M = 1.57 M
D.
The molality of KCl is:
m = moles of KCl / kilograms of solvent
m = 0.376 mol / 0.225 kg
m = 1.67 m
One mole of air undergoes a Carnot cycle. The hotreservoir is at 800oC and the cold reservoir is at 25oC. The pressure ranges between 0.2bar and 60 bar. Determine the net work produced and the efficiency of the cycle.
Answer:
The net work produced = -36737.52 J
The efficiency of the cycle = 72.2%
Explanation:
Given that :
The temperature of the hot reservoir [tex](T__H})[/tex] = 800 °C = (800+273)K
The temperature of the cold reservoir [tex](T__C})[/tex] = 25 °C (25+273)K
Pressure [tex](P__A})[/tex] = 0.2 bar
Pressure [tex](P_B})[/tex] = 60 bar
Rate constant (R) = 8.314
Determination of the efficiency of the cycle (η) is given by the formula:
(η) = [tex]1-\frac{T__C}{T__H}[/tex]
= 1 - [tex]\frac{(800+273)K}{(25+273)K}[/tex]
= 0.722
= 72.2 %
∴ The efficiency of the cycle = 72.2 %
However, the heat given along the initial hot isothermal path [tex](Q__H})[/tex] is equal to the work done which is given by the equation;
[tex]Q__H}=nRT__H}In\frac{V_b}{V_a}[/tex]
[tex]Q__H}=nRT__H}In\frac{P_a}{P_b}[/tex]
substituting our data from the given parameters above; we have:
[tex]= 1 * 8.314 * (800+273) *In (\frac{0.2}{60} )[/tex]
= -50882.99 J
To determine the net work produced; we have:
[tex]W_{net}[/tex] = η[tex]Q__H[/tex]
= 0.722 × (-50882.99 J)
= -36737.52 J
∴ The net work produced = -36737.52 J
The net work produced and the efficiency of the cycle is: [tex]{W_{net} = 111814.54 \text{ J}}[/tex], [tex]{\eta = 72.2\%}[/tex]
To solve this problem, we will use the principles of thermodynamics and the characteristics of a Carnot cycle. The net work produced by a Carnot cycle and its efficiency can be determined using the temperatures of the hot and cold reservoirs and the ideal gas law.
First, let's convert the temperatures from Celsius to Kelvin, which is necessary for the calculations:
- The temperature of the hot reservoir, [tex]\( T_{hot} \), is \( 800^\circ C + 273.15 = 1073.15 K \).[/tex]
- The temperature of the cold reservoir, [tex]\( T_{cold} \), is \( 25^\circ C + 273.15 = 298.15 K \).[/tex]
The efficiency of a Carnot cycle is given by the formula:
[tex]\[ \eta = 1 - \frac{T_{cold}}{T_{hot}} \][/tex]
Substituting the temperatures in Kelvin:
[tex]\[ \eta = 1 - \frac{298.15 K}{1073.15 K} \][/tex]
[tex]\[ \eta = 1 - 0.278 \][/tex]
[tex]\[ \eta = 0.722 \text{ or } 72.2\% \][/tex]
The net work produced in a Carnot cycle can also be expressed in terms of the heat added and the efficiency:
[tex]\[ W_{net} = Q_{in} \cdot \eta \][/tex]
where [tex]\( Q_{in} \)[/tex] is the heat added from the hot reservoir.
Since the process involves one mole of an ideal gas, we can use the specific heat capacity at constant volume, [tex]\( C_v \)[/tex], to find [tex]\( Q_{in} \)[/tex]:
[tex]\[ Q_{in} = n \cdot C_v \cdot (T_{hot} - T_{cold}) \][/tex]
For an ideal diatomic gas, [tex]\( C_v = \frac{5}{2}R \)[/tex], where [tex]\( R \)[/tex] is the ideal gas constant [tex](8.314 J/(mol\cdot K)).[/tex]
Substituting the values:
[tex]\[ Q_{in} = 1 \text{ mol} \cdot \frac{5}{2} \cdot 8.314 \text{ J/(mol\cdot K)} \cdot (1073.15 K - 298.15 K) \][/tex]
[tex]\[ Q_{in} = \frac{5}{2} \cdot 8.314 \text{ J/(mol\cdot K)} \cdot 775 \text{ K} \] \[ Q_{in} = 20 \text{ mol} \cdot 8.314 \text{ J/(mol\cdot K)} \cdot 775 \text{ K} \] \[ Q_{in} = 155027 \text{ J} \][/tex]
Now, we can calculate the net work produced:
[tex]\[ W_{net} = Q_{in} \cdot \eta \] \[ W_{net} = 155027 \text{ J} \cdot 0.722 \] \[ W_{net} = 111814.54 \text{ J} \][/tex]
Therefore, the net work produced by the Carnot cycle is approximately [tex]\( 111814.54 \text{ J} \)[/tex] and the efficiency of the cycle is [tex]\( 72.2\% \).[/tex]
The final answer for the net work produced and the efficiency of the cycle is: [tex]\[ \boxed{W_{net} = 111814.54 \text{ J}} \][/tex], [tex]\[ \boxed{\eta = 72.2\%} \][/tex]
The answer is: [tex]\eta = 72.2\%.[/tex]
Which is/are part of the macroscopic domain of solutions and which is/are part of the microscopic domain: boiling point elevation, Henry’s law, hydrogen bond, ion-dipole attraction, molarity, nonelectrolyte, osmosis, solvated ion?
Answer:
Macroscopic domain: Boiling point elevation, Henry's law, molarity, osmosis.
Microscopic domain: Hydrogen bond, ion-dipole attraction, nonelectrolyte, solvated ion.
Explanation:
A solution is composed of a solute (in high quantity) and one or more solute, which are dissolved in it. The properties of the solution can be characterized and measured in the macroscopic domain, or the microscopic domain when it's observed in the interactions with the molecules.
Boiling point elevation: It happens because the nonvolatile solvents interact with the solute, and so it will be difficult to boil it. The boiling point is a property of all the substance, and so, it can be noticed in the macroscopic domain.
Henry's law: States that the solubilization of a gas in a liquid depends on the partial pressure of the gas and by a proportional constant. Thus, the solubility of a gas is how much moles are dissolved in the volume of the solution, and so it's part of the macroscopic domain.
Hydrogen bond: It's an intermolecular interaction that happens in polar molecules that have bonds between hydrogen and a high electronegative element (N, O, or F). So, it's part of the microscopic domain.
Ion-dipole attraction: It's also an interaction that happens between an ion and a polar compound, so it's part of the microscopic domain.
Molarity: It represents how much moles of the solute is dissolved in the solution, so it's part of the macroscopic domain.
Nonelectrolyte: An electrolyte compound is the one which dissociates or ionizes, in the solvent, and because of that the solution can conduct electricity. A nonelectrolyte doesn't have this property. Because it depends on how the ions and molecules behave in solution, it's part of the microscopic domain.
Osmosis: Is the property of the solvent to go through a membrane from a side with fewer solutes (less concentrated) to another with more solute (high concentrated). So, it depends on the total amount of the solute, and so it's part of the macroscopic domain.
Solvated ion: A solvated ion is an ion that is surrounded by another ion, or by molecules, such water. So, it's part of the microscopic domain.
In the reaction CaCO3 → CaO + CO2 100 grams of calcium carbonate (CaCO3) is observed to decompose upon heating into 56 grams of calcium oxide (CaO) and 44 grams of carbon dioxide (CO2). This is an illustration of
Final answer:
In the given reaction, 100 grams of calcium carbonate decomposed to form 56 grams of calcium oxide and 44 grams of carbon dioxide. This observation is in agreement with the law of conservation of mass.
Explanation:
The given reaction: CaCO3 → CaO + CO2
According to the reaction, 1 mole of CaCO3 decomposes to form 1 mole of CaO and 1 mole of CO2. The molar mass of CaCO3 is 100.09 g/mol. Therefore, the molar mass of CaO and CO2 should be the same, which is 56.08 g/mol. The given mass of CaCO3 is 100 g, so the moles of CaCO3 are:
(100 g / 100.09 g/mol) = 0.999 mol
Since 1 mole of CaCO3 decomposes to form 1 mole of CaO and 1 mole of CO2, the moles of CaO produced will be:
0.999 mol
The molar mass of CaO is 56.08 g/mol, so the mass of CaO produced will be:
(0.999 mol) * (56.08 g/mol) = 55.88 g
Therefore, the observed mass of CaO produced is 56 g, which is in agreement with the law of conservation of mass.
The reaction CaCO₃ → CaO + CO₂ illustrates 5. the Law of Conservation of Matter
The given reaction CaCO₃ → CaO + CO₂ demonstrates the Law of Conservation of Matter.
According to this law, matter cannot be created or destroyed in a chemical reaction. If you start with 100 grams of calcium carbonate (CaCO₃), it decomposes into 56 grams of calcium oxide (CaO) and 44 grams of carbon dioxide (CO₂). Therefore, the total mass of the products (56 g + 44 g = 100 g) equals the mass of the reactant (100 g), which confirms that mass is conserved.For example, when heating 10 grams of calcium carbonate (CaCO₃), the products are 4.4 grams of carbon dioxide (CO₂) and 5.6 grams of calcium oxide (CaO).The combined mass of the products is 10 grams, which equals the mass of the reactant, thereby supporting the Law of Conservation of Matter.
Correct question is: In the reaction CaCO₃ → CaO + CO₂ 100 grams of calcium carbonate (CaCO₃) is observed to decompose upon heating into 56 grams of calcium oxide (CaO) and 44 grams of carbon dioxide (CO₂). This is an illustration of
1. the Law of Gravity
2. the Law of Conservation of Energy
3. the Law of Multiple Proportions
4. the conversion of matter into energy
5. thc Law of Conservation of Matter
Write the condensed ground-state electron configurations of these transition metal ions, and state which are paramagnetic:
(a) V³⁺ (b) Cd²⁺ (c) Co³⁺ (d) Ag⁺
Answer and Explanation :
Paramagnetic are those which has unpaired electrons and diamagnetic are those in which all electrons are paired.
(a) V³⁺
The electronic configuration is -
[tex][Ar]3d^1[/tex]
The electrons in 3d orbital = 1 (Unpaired)
Thus, the ion is paramagnetic as the electrons are unpaired.
(b) Cd²⁺
The electronic configuration is -
[tex][Kr]4d^{10}[/tex]
The electrons in 4d orbital = 10 (paired)
Thus, the ion is diamagnetic as the electrons are paired.
(c) Co³⁺
The electronic configuration is -
[tex][Ar]3d^6[/tex]
The electrons in 3d orbital = 6 (Unpaired)
Thus, the ion is paramagnetic as the electrons are unpaired.
(d) Ag⁺
The electronic configuration is -
[tex][Kr]4d^{10}[/tex]
The electrons in 4d orbital = 10 (paired)
Thus, the ion is diamagnetic as the electrons are paired.
Boiling water is frequently used to kill parasites within the water. If you are boiling fresh water, and liquid water remains in the container, one knows that:________.
Answer: hello dear, your question seems incomplete, but, chill out not to worry let me give you one or two things you need to know in order to be able to solve this kind of question in the nearest future, check this out!.
Explanation:
In order to kill parasites and to make the water the be safe from microoganisms, boiling is a great procedure for making sure this happens, that is to say is the act of purification of water. However, when you over-boil water it also depletes the amount of oxygen present in the water.
When you boil water for the purpose of killing germs/ parasites, the PURIFIED PART IS THE WATER VAPOUR, the LIQUID WATER STILL HAS THE DEAD PARASITES IN THEM. That is the reason why the process called DISTILLATION is more efficient in purifying water is more efficient than ordinary boiling of water.
The liquid water remaining in the container after the boiling would have also been purified though, but it will still contain dead contaminants, so, filtering can be done or one can drink the water like that.
A piece of potassium metal is added to water in a beaker. The reaction that takes place is 2K(s) 2H20(/) ..... 2KOH(aq) H2(g) Predict the signs of w, q, liU, and /iH
Answer:
Explanation:
The given reaction is exothermic . So ΔH is negative .
Gas is evolving so work done by gas is positive or w is positive.
Change in internal energy that is ΔU is negative.
q = u - w
u is negative , w is positive so q is negative .
Calculate the moles of O atoms in 0.658 g of Mg(NO3)2.
Answer:
There are 0.0267 moles of oxygen in 0.658 grams of magnesium nitrate.
Explanation:
Mass of magnesium nitrate = m = 0.658 g
Molar mass of magnesium nitrate = M = 148 g/mol
Moles of magnesium nitrate = n
[tex]n=\frac{m}{M}=\frac{0.658 g}{148 g/mol}=0.004446 mol[/tex]
1 mole of magnesium nitrate has 6 moles of oxygen atoms. Then 0.004446 moles magnesium nitrate will have :
[tex]6\times 0.004446 mol=0.026676 mol\approx 0.0267[/tex]
There are 0.0267 moles of oxygen in 0.658 grams of magnesium nitrate.
To test Döbereiner’s idea, predict:
(a) The boiling point of HBr from the boiling points of HCl (- 84.9°C) and HI (-35.4°C) (actual value = -67.0°C)
(b) The boiling point of AsH₃ from the boiling points of PH₃ (- 87.4°C) and SbH₃ (-17.1°C) (actual value = -55°C)
Answer:
a) Approximate boiling point of HBr = -60.15 °C
b) Approximate boiling point of AsH₃ = -52.25 °C
Explanation:
Döbereiner stated that some elements could be arranged in groups of 3 similar elements ( known as "triads) , and the element of the middle ( elements are ordered with respect to their atomic mass) would have properties between the other 2 ( the average value)
a) In the first case the triad would be the halogen triad ( Cl , Br and I ) . And according to Döbereiner , the boiling point of HBr should be the average of HCl and HI . Therefore
Approximate boiling point of HBr = [(- 84.9°C) + (-35.4°C)]/2 = -60.15 °C
b) Simmilarly for AsH₃ , PH₃ and SbH₃ , the boiling point of AsH₃ would be
Approximate boiling point of AsH₃ = [(- 87.4°C) + (-17.1°C)]/2 = -52.25 °C
If 0.0526 mol CaCl 2 is dissolved in water to make a 0.110 M solution, what is the volume of the solution? V = mL
Answer:
478mL
Explanation:
We can obtain the molarity of a solution by:
Molarity = mole /Volume(L)
From the question,
Number of mole = 0.0526mol
Molarity = 0.110M
Volume =?
Volume = mole /Molarity
Volume = 0.0526/0.11 = 0.478L
But
1L = 1000mL
0.478L = 0.478 x 1000 = 478mL
The plot shows the absorbance spectra for solutions of caffeine, benzoic acid, and Mountain Dew® soda, each in 0.010 M HCl . A plot contains three spectra with Absorbance on the y axis and wavelength in nanometers on the x axis. Absorbance measurements range from 0.0 to 1.5, with increments every 0.2. Wavelength measurements range from 200 to 300, with icrements every 100 nanometers. A note states that All solutions contain 0.010 molar H C L. The spectrum for benzoic acid at a concentration of 8.74 milligrams per liter, begins at an absorbance of about 1.3 and 200 nanometers. Absorbance sharply decreases to 0.2 at 210 nanometers, then rises and peaks at an absorbance close to 0.8 and 228 nanometers. The spectrum for a 1 to 50 dilution of Mountain Dew soda begins at an absorbance of 1.5 and 200 nanometers, then sharply decreases in absorbance to 0.6 at 215 nanometers, then rises and peaks at absorbance close to 0.75 at 228 nanometers, decreases, then peaks again at absorbance 0.27 at 275 nanometers. The spectrum for a caffeine at a concentration of 10.88 milligrams per liter begins at an absorbance of 1.45 at 200 nanometers, then rises slightly, with a peak at absorbance 1.5 at 205 nanometers, then decreases sharply in absorbance until 0.2 at 245 nanometers. The plot then peaks again at an absorbance close to 0.6 at 270 nanometers. What is the approximate absorbance of benzoic acid at 228 nm?
Complete Question
The diagram of the complete question is shown on the first uploaded image.
Answer:
a) The approximate absorbance of benzoic acid at 228 nm? : A = 0.8
b) The molar absorptivity(∈)
of benzoic acid at 228 nm? : ∈ = [tex]1.12 * 10^{4} M^{-1} cm^{-1}[/tex]
Explanation:
Looking at the absorbance spectra, we can see that the approximate absorbance of benzoic acid at 228 is 0.8.
mass concentration of benzoic acid = [tex]8.74 \frac{mg}{L} =8.74 * 10^{-3} \frac{g}{L}[/tex]
the molar concentration of benzoic acid = (mass concentration of benzoic acid) / (molar mass of benzoic acid )
molar concentration of benzoic acid = [tex](8.74 *10^{-3} \frac{g}{L} ) /(122.12\frac{g}{mol} )[/tex]
molar concentration of benzoic acid = [tex]7.157 * 10^{-5}M[/tex]
molar absorptivity (∈) of benzoic acid = (absorbance) /[ (molar concentration of benzoic acid ) × (path length) ]
∈ = (0.8) / [ ([tex]7.157 *10^{-5}M[/tex]) ×(1.00 cm)]
= [tex]1.12 * 10^{4} M^{-1} cm^{-1}[/tex]
The approximate absorbance of benzoic acid at 228 nanometers as described in the provided spectra plot is close to 0.8. The absorbance reveals the amount of light absorbed by the solution, which can further be used to determine the concentration of a compound.
Explanation:Based on the provided description of the absorbance spectra, the approximate absorbance of benzoic acid at 228 nanometers is close to 0.8. In many analytical procedures, the values of absorbance help determine the concentration of a compound.
It's important to understand that absorbance is a measure of the quantity of light absorbed by a solution, in this case, the solution of benzoic acid. The higher the absorbance, the more light is absorbed and less is transmitted through the solution. Each compound has a unique absorbance spectrum, serving like a 'fingerprint' which helps in identifying substances.
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Functional groups confer specific chemical properties to the molecules of which they are a part. In this activity, you will identify which compounds exhibit certain chemical properties as well as examples of those six different compounds.
Answer:
This question is incomplete, here is the complete question:
Functional groups confer specific chemical properties to the molecules of which they are a part. In this activity, you will identify which compounds exhibit certain chemical properties as well as examples of those six different compounds.
(a) alcohol: is highly polar and may act as a weak acid (OH)
(b) carboxylic acid: acts as an acid (COOH)
(c) aldehyde: may be a structural isomer of a ketone (C=O)
(d) thiol: forms disulfide bonds (S-H)
(e) amine: acts as a base (NH2)
(f) organic phosphate: contributes negative charge (PO4)
Explanation:
Functional groups are groups of atoms attached to the carbon skeleton of an organic compounds and confers some particular properties. For example:
(a) alcohol: is highly polar and may act as a weak acid (OH)
. In this functional group, oxygen is very electronegative and tend to attract electrons. Water is attracted to this group and because of this, compounds that have OH group will disolve in water. Organic compounds with this functional group are alcohols and carbohydrates for example.
(b) carboxylic acid: acts as an acid (COOH)
. The two electronegative oxygens of this group keep electrons attached to them and do not share them with tha Hydrogen atom. Because of this, the hydrogen atom can dissociates from the molecule, giving an acid.
(c) aldehyde: may be a structural isomer of a ketone (C=O)
. As in the case of -OH group, oxygen of this group is very electronegative. When the group is presents at the end of the carbon skeleton we cal it aldehyde, while when it is in another part of carbon structure we call it ketone.
(d) thiol: forms disulfide bonds (S-H)
. When two thiol groups (S-H) are oxidazed, losting their hydrogen atoms, they form disulfide bonds that gives stability to the molecules that contains them. An example of this is found in proteins when two aminoacids with thiol groups (cysteine, for example) interact and form disulfide bonds that stabilizes the protein.
(e) amine: acts as a base (NH2)
. The nitrogen atom of this groups is slightly electronegative so it tends to pick up hydrogen ions from the surroundings given rise to a base. This group i typicall of aminoacids (glycine, for example)
(f) organic phosphate: contributes negative charge (PO4). In this group, phosphorus easily changes its oxydation state, thus, giving rise to a compound with electronegative oxygens. An important biological molecule that contains this group is ATP
Functional groups are important components of organic molecules, conferring specific chemical properties to the molecules. Common functional groups include hydroxyl, methyl, carbonyl, carboxyl, amino, phosphate, and sulfhydryl. The presence of these groups can greatly affect the chemical properties and function of the molecule.
Explanation:Functional groups are vital components of organic molecules, conferring specific chemical properties upon the molecules in which they occur. These groups are attached to a 'carbon backbone' of chains or rings of carbon atoms, with possible substitutions of elements like nitrogen or oxygen. For example, the C-Cl portion of the chloroethane molecule is a functional group imparting specific chemical reactivity. The nature of the functional groups in an organic molecule are significant determinants of its chemical properties.
Functional groups take part in particular chemical reactions. Some of the important functional groups include hydroxyl, methyl, carbonyl, carboxyl, amino, phosphate, and sulfhydryl. These functional groups may attach to the carbon backbone at various points along the chain or ring structure. The presence of these groups majorly contributes to the varying chemical properties of different organic molecules and their functions in living organisms.
For example, carboxyl groups (-COOH) confer acidic properties to a molecule, while amine groups (NH₂) make a molecule more basic. Molecules with identical molecular formulas may have different structures due to variations in their functional groups, morphing into different types of isomers.
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Electrophiles for the electrophilic aromatic substitution reactions have to be very strong to react with the stable aromatic rings. A nitronium ion is needed for nitration of aromatic rings. Complete the mechanism of the formation of the nitronium ion from concentrated nitric acid in concentrated sulfuric acid.
Answer: The nitronium ion is a strong electrophile
Explanation:
The detailed mechanism of the reaction is shown in the images attached. The flow of electrons has been shown with arrows. HNO3 is first protonated by H2SO4 this protonated specie H2NO3+ now forms H2O and NO2+.
The nitronium ion is formed when concentrated sulfuric acid protonates nitric acid, which then loses water to produce the reactive electrophile NO2+ needed for electrophilic aromatic substitution reactions.
Explanation:The formation of the nitronium ion (NO2+) from concentrated nitric acid in concentrated sulfuric acid is a crucial step in the electrophilic aromatic substitution mechanism. The process begins with the protonation of nitric acid by sulfuric acid, creating the nitronium ion and water. Specifically, sulfuric acid acts as a strong acid and protonates the nitric acid, which loses a water molecule and forms the nitronium ion. This positively charged electrophile is highly reactive and capable of attacking the electron-rich aromatic ring, initiating a substitution reaction.
In the context of aromatic substitutions, the nitronium ion is very strong and reactive enough to overcome the stability of the aromatic ring's delocalized electrons. Its formation is necessary because aromatic compounds don't readily react with partial positive electrophiles, making the full cation electrophile essential for the reaction to proceed.