At 39.5 o C, the vapor pressure of pure acetone (MM = 58.08 g/mol) is 400.0 torr. If 15.0 grams of an unknown molecule is dissolved in 485.0 g acetone, the vapor pressure decreases to 361.8 torr. What is the molar mass of the solute?

Answer:

Light as a wave

1. Young's Double Slit Experiment

2. Davisson-Germer Experiment

Light as a particle

1. Einsteins Photoelectric Effect Phenomenon

2.  Diffraction Phenomenon of Particles

Evidence for light as a wave includes diffraction and interference patterns, while evidence for the particle model includes the photoelectric effect and emission spectra.

The mid-17th century debate on whether light is a wave or a particle extended well into the 20th century until revolutionary concepts by Planck and Einstein. There is evidence for both the wave model and the particle model of light. Two pieces of evidence for the wave nature of light are diffraction and interference patterns, as seen in Thomas Young's double-slit experiment.

Diffraction occurs when light encounters an obstacle, spreading out as a result, and interference patterns occur when waves overlap and combine in constructive or destructive ways. Conversely, evidence for the particle nature includes phenomena like the photoelectric effect, as explained by Einstein, where light knocks electrons from a material, and the behavior of emission spectra, where individual energy quanta or "photons" are emitted from atoms.

Answer:

Concentration of stock solution in g/L = 5.0g/L

Concentration of stock solution in mol/L = 0.00117 mol/L or 0.00117 M

Explanation:

Concentration in mol/L = (Concentration in g/L)/(Molar mass)

Mass of (NH₄)₃Fe(ox)₃.3H₂O stock = 125mg = 0.125g

Volume of stock solution required = 25mL = 0.025 L

Concentration in g/L = 0.125/0.025 = 5.0 g/L

Molar Mass of (NH₄)₃Fe(ox)₃.3H₂O = (NH₄)₃Fe(C₂O₄)₃.3H₂O = 428.0632 g/mol

Concentration in mol/L = 5/428.0632 = 0.00117 mol/L = 0.00117 M

Hope this helps!!!

Explanation:

a) Bohr model is perfect for atoms that have single electron and fortunately both Be3+ ion and H atom have one electron so, Bohr model can easily and accurately applied to predict the spectrum of Be3+ and H atom.

b) The energy of an atom in  Bohr model is given by

[tex]E= \frac{-13.6z^2}{n^2}[/tex]

the values of z for H atom and Be3+ ion are 1 and 4 respectively. Hence, energy of atoms would be different for both atoms. Hence, line spectra to be identical is not possible.

The energy of a photon can be calculated using Planck's equation (E = hf). Given the radio wave frequency of 3.8 x 10^10 Hz and using Planck's constant (6.626 x 10^-34 J·s), the energy of one photon of this radiation is 2.52 x 10^-23 Joules.

To find the energy of one photon of radiation, we need to use Planck's formula: E = hf. Here, 'E' represents energy, 'h' is Planck’s constant (6.626 x 10^-34 J·s), and 'f' is frequency. Given that the frequency (f) of the wave is 3.8 x 10^10 Hz, we substitute these values into Planck's equation:

E = hf = (6.626 x 10^-34 J·s) (3.8 x 10^10 Hz) = 2.52 x 10^-23 J

So, the energy of one photon of this radiation is 2.52 x 10^-23 Joules.

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Answer:

0.004522 moles of hydrogen peroxide molecules are present.

Explanation:

Mass by mass percentage of hydrogen peroxide solution = w/w% = 3%

Mass of the solution , m= 5.125 g

Mass of the hydrogen peroxide = x

[tex]w/w\% = \frac{x}{m}\times 100[/tex]

[tex]3\%=\frac{x}{5.125 g}\times 100[/tex]

[tex]x=\frac{3\times 5.125 g}{100}=0.15375 g[/tex]

Mass of hydregn pervade in the solution = 0.15375 g

Moles of hydregn pervade in the solution :

[tex]=\fraC{ 0.15375 g}{34 g/mol}=0.004522 mol[/tex]

0.004522 moles of hydrogen peroxide molecules are present.

To determine the number of moles of hydrogen peroxide molecules present in the solution, multiply the mass of the solution by the mass percent of hydrogen peroxide. Then, convert the mass of hydrogen peroxide to moles using its molar mass. The number of moles of hydrogen peroxide molecules is approximately 0.00452.

To determine the number of moles of hydrogen peroxide molecules present, we first need to calculate the mass of hydrogen peroxide in the solution. We can do this by multiplying the mass of the solution (5.125 g) by the mass percent of hydrogen peroxide (3.00% or 0.03).

Mass of hydrogen peroxide = 5.125 g × 0.03 = 0.15375 g

Next, we need to convert the mass of hydrogen peroxide to moles using its molar mass. The molar mass of hydrogen peroxide (H2O2) is 34.0146 g/mol.

Moles of hydrogen peroxide = 0.15375 g ÷ 34.0146 g/mol ≈ 0.00452 mol

Therefore, there are approximately 0.00452 moles of hydrogen peroxide molecules present.

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Answer: Reversible competitive inhibition

Explanation:

In the case of reversible competitive inhibition, an inhibitor molecule competes with the substrate for binding to the active site of the enzyme. The inhibitor blocks the active site of the enzyme. Thus the enzyme substrate complex do not form. The structure of the inhibitor is similar to the substrate thus also have the binding affinity with the enzyme. The process is reversible because the inhibitor will leave the enzyme it exerts no permanent effect on the enzyme.

The given situation is the example of reversible competitive inhibition as substrate remain unchanged and the enzyme was not able to act on the substrate chemically may be due to inhibition of the function of the enzyme.

Explanation:

Ksp of NiCO3 = 1.4 x 10^-7

Ksp of CuCO3 = 2.5 x 10^-10

Ionic equations:

NiCO3 --> Ni2+ + CO3^2-

CuCO3 --> Cu2+ + CO3^2-

[Cu2+][CO3^2-]/[Ni2+][CO3^2-]

= (2.5* 10^-10)/(1.4* 10^-7)

= 0.00179.

[Cu2+]/[Ni2+]

= 0.00179

= 0.00179*[Ni2+]

If all of Cu2+ is precipitated before Na2CO3 is added.

= 0.00179 * (0.25)

The amount of Cu2+ not precipitated = 0.000448 M

The percent of Cu2+ precipitated before the NiCO3 precipitates = concentration of Cu2+ unprecipitated/initial concentration of Cu2+ * 100

= 0.000448/0.25 * 100

= 0.18%

Therefore, percentage precipitated = 100 - 0.18

= 99.8%

The two metal ions can be separated by slowly adding Na2CO3. Thus that is the unpptd Cu2+.

The metal ions can be separated by slowly adding Na2CO3 based on the relative solubilities of their carbonates. Nickel carbonate (NiCO3) is less soluble than copper carbonate (CuCO3), allowing the selective precipitation of nickel ions before copper ions.

To determine if the metal ions can be separated by slowly adding Na2CO3, we need to consider the solubility of the metal carbonates. Nickel carbonate (NiCO3) and copper carbonate (CuCO3) both have low solubilities, but it is crucial to examine their relative solubilities. If one carbonate is significantly less soluble than the other, it can be selectively precipitated first.

In this case, NiCO3 is less soluble than CuCO3. Therefore, by slowly adding Na2CO3 to the solution, we can precipitate the majority of the Ni2+ ions as NiCO3 before CuCO3 begins to precipitate. This satisfies the condition that 99% of the metal ion must be precipitated before the other metal ion begins to precipitate.

Therefore, it is possible to separate the nickel and copper ions in the solution by slowly adding Na2CO3.

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Answer:

MG is less polar  

Explanation:

The structures of crystal violet (CV) and malachite green (MG) are shown in Figures 1 and 2, respectively.  

The obvious difference is that CV has an extra dimethylamino group (polar).

Alumina is a polar adsorbent, so it retains the more polar substances more strongly and they are eluted last.

MG is less polar than CV, so it is retained less strongly and is eluted first.

Answer:

It is because of difference in polarization

Explanation: Benzoic acid is a non-polar strong acid with low solubility and no internal stabilizing structures to favor the carboxylic acid . Benzoate ion is polar which has high solubility due to being polar.

The water solubility of benzoic acid is much lower than that of the benzoate ion because of the difference in polarization.

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The question is incomplete , complete question is:

Arrange the following H atom electron transitions in order of increasing frequency of the photon absorbed or emitted:

(a) n = 2 to n = 4

(b) n = 2 to n = 1

(c) n = 2 to n = 5

(d) n = 4 to n = 3

Answer:

Hence the order of the transition will be : d < a < c < b

Explanation:

[tex]E_n=-13.6\times \frac{Z^2}{n^2}ev[/tex]

where,

[tex]E_n[/tex] = energy of [tex]n^{th}[/tex] orbit

n = number of orbit

Z = atomic number

Energy of n = 1 in an hydrogen atom:

[tex]E_1=-13.6\times \frac{1^2}{1^2}eV=-13.6 eV[/tex]

Energy of n = 2 in an hydrogen atom:

[tex]E_2=-13.6\times \frac{1^2}{2^2}eV=-3.40eV[/tex]

Energy of n = 3 in an hydrogen atom:

[tex]E_3=-13.6\times \frac{1^2}{3^2}eV=-1.51eV[/tex]

Energy of n = 4 in an hydrogen atom:

[tex]E_4=-13.6\times \frac{1^2}{4^2}eV=-0.85 eV[/tex]

Energy of n = 5 in an hydrogen atom:

[tex]E_5=-13.6\times \frac{1^2}{5^2}eV=-0.544 eV[/tex]

a) n = 2 to n = 4 (absorption)

[tex]\Delta E_1= E_4-E_2=-0.85eV-(-3.40eV)=2.55 eV[/tex]

b) n = 2 to n = 1 (emission)

[tex]\Delta E_2= E_1-E_2=-13.6 eV-(-3.40eV)=-10.2 eV[/tex]

Negative sign indicates that emission will take place.

c) n = 2 to n = 5 (absorption)

[tex]\Delta E_3= E_5-E_2=-0.544 eV-(-3.40eV)=2.856 eV[/tex]

d) n = 4 to n = 3 (emission)

[tex]\Delta E_4= E_3-E_4=-1.51 eV-(-0.85 eV)=-0.66 eV[/tex]

Negative sign indicates that emission will take place.

According to Planck's equation, higher the frequency of the wave higher will be the energy:

[tex]E=h\nu [/tex]

h = Planck's constant

[tex]\nu [/tex] frequency of the wave

So, the increasing order of magnitude of the energy difference :

[tex]E_4<E_1<E_3<E_2[/tex]

And so will be the increasing order of the frequency of the of the photon absorbed or emitted. Hence the order of the transition will be :

: d < a < c < b

Final answer:

The order of increasing frequency of photon absorbed or emitted for the H atom electron transitions is (a) n = 2 to n = 4, (c) n = 2 to n = 5, (b) n = 2 to n = 1, and (d) n = 2 to n = 1.

Explanation:

The frequency of a photon absorbed or emitted by a hydrogen atom is related to the energy difference between the initial and final energy levels. The energy difference decreases as the value of n increases, so (a) n = 2 to n = 4 has the lowest frequency, followed by (c) n = 2 to n = 5, (b) n = 2 to n = 1, and finally, (d) n = 2 to n = 1 has the highest frequency.

Explanation:

Ionization energy is defined as the energy required to remove the most loosely bound electron from a neutral gaseous atom.

When we move across a period from left to right then there occurs a decrease in atomic size of the atoms. Therefore, ionization energy increases along a period.

But when we move from top to bottom in a group then there occurs an increase in size of the atoms. Hence, ionization energy decreases along a group.

(a)  As Sb, Sn and I are all period 5 elements. Hence, these elements are arranged in order of increasing [tex]IE_{1}[/tex] as follows.

                             Sn < Sb < I

(b)  As Sr, Ca, and Ba are all elements of group 2a. Hence, these elements are arranged in order of increasing [tex]IE_{1}[/tex] as follows.

                            Ba < Sr < Ca

Answer:

Explanation:

150 mM NaCl = 0.15 M NaCl

500 ml of 0.15 M NaCl = 500 x 0.15 ml of M NaCl

= 75 ml of M NaCl

M.W = 40 g

1000 ml of M NaCl requires 40 g

75 ml of M NaCl requires (40/1000) x75

= 3 g

We shall take 500 ml of water in a graduated cylinder . Then we weigh 3 g of salt and add it to 500 ml of water and mix it . We shall get 500 ml of 150mM NaCl.

Final answer:

To make 500mL of 150mM NaCl solution, calculate the required mass of NaCl (4.383 grams), dissolve it in less than 500mL of DI water, and then adjust the volume to 500mL using a graduated cylinder for precise measurement.

Explanation:

To make 500 mL of 150mM NaCl solution, you first need to calculate the amount of NaCl required using the molarity formula, which is Molarity (M) = moles of solute / liters of solution. Given that the molar mass of NaCl is 58.44g/mol (not 40g/mol as incorrectly stated in the question), to prepare a 150mM (0.150M) NaCl solution, the calculation is as follows:

Calculate the moles of NaCl needed: moles = 0.150M * 0.500L = 0.075 moles.Convert moles to grams: grams = moles * molar mass = 0.075 mol * 58.44 g/mol = 4.383 grams.Measure out 4.383 grams of NaCl using an electronic scale.Dissolve the measured NaCl in less than 500 mL of di-ionized water (DI water) in a beaker.Transfer the solution to a 500 mL graduated cylinder and add DI water until the volume reaches 500 mL to ensure the correct concentration.

It is important to dissolve the NaCl in less than the final volume before adjusting up to the final desired volume. This approach ensures accuracy in the concentration of the resulting solution.

Final answer:

The molality of the sodium hydroxide (NaOH) solution is 0.54 mol/kg.

Explanation:

The molality of a solution is defined as the number of moles of solute per kilogram of solvent. In this case, the solute is sodium hydroxide (NaOH) and the solvent is water.

To calculate the molality, we need to first convert the given mass of NaOH to moles using its molar mass, which is 40.0 g/mol. Then, we need to convert the mass of the solution to kilograms using the density of the solution, which is 1.15 g/mL.

Using the given information:

Mass of NaOH = 24.8 g/L

Density of solution = 1.15 g/mL

Molar mass of NaOH = 40.0 g/mol

The molality can be calculated as follows:

Answer:

The answer would be A. the number of electrons in the outermost electron shell.

Explanation:

These are called valence electrons which are transferred, shared, and rearranged by creating covalent bonds producing new substances.

Hope this helped! :)

The type of chemical reaction an atom chooses is determined by the number of the outermost electrons in the outermost shell of an atom.

About the importance of electrons the below points should be noted;

Therefore the answer is the number of electrons in the outermost electron shell.

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Answer: C. gods who are thought to be powerful, who have an interest in human affairs, and who merit worship.

Explanation: Theistic religion is a religious belief in the existence of a supreme being in the form of God or gods who control the affairs of men. Theism is classified into different categories from Monotheism ( the belief in the existence of only one God), Polytheism ( the belief in the presence of different supreme beings), Pantheism (where it is believed that the universe in itself is a God),Autotheism( a believe that each person has a divine nature,it means that divinity exists in us), etc.

Theism is derived from the Greek word known as "Theo" which means God.

Answer :

(a) Number of electrons in an atoms is, 2

(b) Number of electrons in an atoms is, 10

(c) Number of electrons in an atoms is, 10

Explanation :

There are 4 quantum numbers :

Principle Quantum Numbers : It describes the size of the orbital. It is represented by n. n = 1,2,3,4....

Azimuthal Quantum Number : It describes the shape of the orbital. It is represented as 'l'. The value of l ranges from 0 to (n-1). For l = 0,1,2,3... the orbitals are s, p, d, f...

Magnetic Quantum Number : It describes the orientation of the orbitals. It is represented as . The value of this quantum number ranges from . When l = 2, the value of

Spin Quantum number : It describes the direction of electron spin. This is represented as . The value of this is  for upward spin and  for downward spin.

Number of electrons in a sublevel = 2(2l+1)

(a) 2s

n = 2

Value of 'l' for 's' orbital : l = 0

Number of electrons in an atoms = 2(2l+1) = 2(2×0+1) = 2

(b) n = 3, l = 2

Number of electrons in an atoms = 2(2l+1) = 2(2×2+1) = 10

(c) 6d

n = 2

Value of 'l' for 'd' orbital : l = 2

Number of electrons in an atoms = 2(2l+1) = 2(2×2+1) = 10

In quantum chemistry, the 2s sublevel can hold 2 electrons, the n = 3, l = 2 sublevel (3d) can hold 10 electrons, and the 6d sublevel can also hold 10 electrons.

In quantum chemistry, specific sublevels or orbitals within an atom can hold certain numbers of electrons.

(a) The 2s sublevel can hold a maximum of 2 electrons. This is because 's' orbitals can contain up to 2 electrons.

(b) For n = 3, l = 2, this refers to the 3d orbital. 'd' orbitals can hold a maximum of 10 electrons, so 10 electrons can exist in this energy level.

(c) For the 6d orbital, it can also hold up to 10 electrons, as it is also a 'd' orbital.

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Answer: hydroxyl group

Explanation:

Answer:

The molar mass of the compound is 720.8 g/mol

Explanation:

Let's apply the colligative property of Osmotic pressure to solve this.

Formula is π = M . R . T

where π is pressure (atm)

M is molarity (mol/L)

R, Universal Constant Gases

T, Absolute T° ( T° in K = T° in C + 273)

Let's replace the data:

8.44 Torr = M . 0.082 L.atm/mol.K . 298K

As we have the pressure in Torr, we must convert to atm, to work properly.

8.44 Torr . 1 atm/ 760 Torr = 0.0111 atm

0.0111 atm = M . 0.082 L.atm/mol.K . 298K

0.0111 atm / (0.082 L.atm/mol.K . 298K) = M  → 4.54×10⁻⁴ mol/L

So molarity is the moles of solute (mass (g) / molar mass) / volume (L)

Let's convert the volume to L → 279.6 mL . 1L / 1000 mL = 0.2796 L

4.54×10⁻⁴ mol/L . 02796 L = 1.27×10⁻⁴ moles

This moles are represented by the 91.6 mg, so let's convert the mass of solute from mg to g

91.6 mg . 1 g / 1000 mg = 0.0916 g

Molar mass → g/mol → 0.0916 g / 1.27×10⁻⁴ moles → 720.8 g/mol

Answer:

4.25% is the final concentration of phosphoric acid.

Explanation:

Initial concentration of phosphoric acid = [tex]C_1=85\%=0.85[/tex]

Initial volume of phosphoric acid = [tex]V_1=50 mL[/tex]

Final concentration of phosphoric acid = [tex]C_2=?[/tex]

Final volume of phosphoric acid = [tex]V_2=1 L=1000 mL[/tex]

( 1L = 1000 mL)

[tex]C_1V_1=C_2V_2[/tex]

[tex]C_2=\frac{C_1times V_1}{V_2}[/tex]

[tex]=\frac{0.85\times 50 mL}{1000 mL}=0.0425=4.25%[/tex]

4.25% is the final concentration of phosphoric acid.

Explanation:

A. CeCl

Cerium chloride.

Metal: Ce+

B. SrBr2

Strontium chloride.

Metal: Sr2+

C. K2O

Potassium oxide.

Metal: K+

D. LiF

Lithuim fluoride.

Metal: Li+

Chlorine (Cl) creates an anion with a -1 charge, but the metal cerium (Ce) only forms one type of ion with a +3 charge. As a result, the substance is known as cerium(III) chloride.

a) CeCl: Cerium(III) chloride

Whereas bromine (Br) generates an anion with a -1 charge, the metal strontium (Sr) only forms one sort of ion with a +2 charge in this combination. As a result, the substance is known as strontium bromide.

b) SrBr2: Strontium bromide

In this molecule, oxygen (O) generates an anion with a -2 charge whereas the metal potassium (K) only produces one sort of ion with a +1 charge. The substance is referred to as potassium oxide as a result.

c) K2O: Potassium oxide

Lithium is the only element present in this combination (Li). As lithium only ever produces an ion with a positive charge, it is known simply as lithium.

d) Li: Lithium

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Answer:

The new volume is 5.37 L

Explanation:

Step 1: Data given

Initial volume = 10.0 L

Initial temperature = 22.0 °C

Initial pressure = 1.00 atm

Final temperature = 202 °C

Final pressure = 3.00 atm

Step 2: Calculate final volume

(P1*V1)/T1  = (P2*V2)/T2

⇒ with P1 = The initial pressure = 1.00 atm

⇒ with V1 = The initial volume = 10.0 L

⇒ with T1 = The initial temperature = 22 °C = 295 Kelvin

⇒ with  P2 = The final pressure = 3.00 atm

⇒ with V2 = The final volume = TO BE DETERMINED

⇒ with T2 = The final temperature = 202 °C = 475 Kelvin

(1.00 * 10.0) / 295 = (3.00 * V2) / 475

10 / 295 = 3V2/ 475

3V2 = 4750/295

V2 = 5.37 L

The new volume is 5.37 L

Answer:

Xenon atoms will have a temperature of 308.25 °C

Explanation:

Step 1: Data given

Molar mass of Cl2 = 70.9 g/mol

Molar mass of Xenon = 131.29 g/mol

Temperatue of Cl2 molecules = 41 °C = 314 K

Step 2: Calculate temperature

The average speed of a gas particle is given by v = √(8RT/πM).

We can simplify this to:

T1/M1 = T2/M2

⇒ with T1 = The temperature of Cl2 molecules = 314 K

⇒ with M1 = the molar mass of Cl2 = 70.9 g/mol

⇒ with T2= The temperature of Xenon = TO BE DETERMINED

⇒ with M2 = The molar mass of Xenon = 131.29 g/mol

314/70.9 = T2/131.29

T2 = 581.4 Kelvin

581.4 Kelvin = 308.25 °C

Xenon atoms will have a temperature of 308.25 °C

Final answer:

To find the temperature at which xenon atoms have the same average speed as Cl2 molecules at 41 degrees Celsius, use the equation for the average speed of gas molecules. Substitute the molar masses of Cl2 and xenon into the equation and solve for temperature. The temperature is approximately 191.89 degrees Celsius.

Explanation:

To determine the temperature at which xenon atoms have the same average speed as Cl2 molecules at 41 °C, we need to use the equation for the average speed of gas molecules:

average speed = sqrt((3 * kB * T) / (molar mass))

where kB is the Boltzmann constant and T is the temperature in Kelvin.

Since the gas molecules we are comparing are different, we need to find the molar mass of Cl2 molecules and xenon atoms. The molar mass of Cl2 is 70.90 g/mol and the molar mass of xenon is 131.29 g/mol.

Substituting the values into the equation, we have:

sqrt((3 * (1.380649 × 10-23) * T) / (70.90)) = sqrt((3 * (1.380649 × 10-23) * (41 + 273.15)) / (131.29))

Simplifying and solving for T, we find that the temperature at which xenon atoms have the same average speed as Cl2 molecules at 41 °C is approximately 191.89 °Celsius.

Answer : The concentration of [tex]K^+[/tex] ion in 0.15 M [tex]K_2S[/tex] is, 0.3 M

Explanation :

The given compound is, [tex]K_2S[/tex]

When [tex]K_2S[/tex] dissociates then it gives potassium ion and sulfide ion.

The balanced dissociation reaction is:

[tex]K_2S\rightarrow 2K^++S^{2-}[/tex]

By the stoichiometry we can say that, 1 mole of [tex]K_2S[/tex] dissociates to give 2 moles of [tex]K^+[/tex] ion and 1 mole of [tex]S^{2-}[/tex] ion.

Or, in terms of concentration we can say that:

0.15 M of [tex]K_2S[/tex] dissociates to give [tex]2\times 0.15M=0.3M[/tex] of [tex]K^+[/tex] ion and 0.15 M of [tex]S^{2-}[/tex] ion.

Thus, the concentration of [tex]K^+[/tex] ion in 0.15 M [tex]K_2S[/tex] is, 0.3 M

The concentration of K+ in a 0.15 M solution of K2S is 0.3 M, calculated by multiplying the concentration of K2S by two, since each unit of K2S produces two K+ ions.

The concentration of K+ in a solution of 0.15 M K2S can be determined by recognizing that each formula unit of K2S produces two K+ ions.

Therefore, to find the concentration of K+, you multiply the concentration of K2S by two:

The concentration of K+ in the solution is 0.3 M, where M stands for molarity, representing moles of solute per liter of solution.

Answer:

Answer in explanation

Explanation:

a. Boron , element 5

Helium has 2 electrons, add to the other 3 to give 5.

Other group members are : Aluminum Al, Gallium Ga, Indium In , Thallium Tl and Nihonium Nh

b. Sulphur, element 16

Neon is 10 , add other 6 electrons to make 16

Other group members are: Oxygen O, selenium Se , Tellurium Te and Polonium Po

c. Lanthanum, element 57

Xenon is 54, add the other 3 electrons to give 57.

Other elements in group : Scandium Sc , Yttrium Y , Actinium Ac, Lutetium Lu and/or Lawrencium Lr

Answer:

. C. a compound in which one or more carbon atoms have double or triple bonds.

Explanation:

An unsaturated hydrocarbon -

It refers to the organic compound , where the carbon atom remains unsaturated with the number of hydrogen atoms , i.e. , maximum number of hydrogen atom a carbon atom can hold is four , and less than four number of hydrogen atom attached to the carbon atom , makes the hydrocarbon unsaturated in nature .

Hence ,

It the carbon atom have one or more number of double or triple bond , then the compound is said to be unsaturated in nature .

Hence , from the question,

The correct option is c.

Answer:

m = 3 moles/kg

Explanation:

This is a problem of freezing point depression, and the formula or expression to use is the following:

ΔT = i*Kf¨*m (1)

Where:

ΔT: Change of temperature of the solution

i: Van't Hoff factor

m: molality of solution

Kf: molal freezing point depression of water (Kf = 1.86 °C kg/mol)

Now, the value of i is the number of moles of particles obtained when 1 mol of a solute dissolves. In this case, we do not know what kind of solution is, so, we can assume this is a non electrolyte solute, and the value of i = 1.

Let's calculate the value m, which is the molality solving for (1):

m =  ΔT/Kf (2)

Finally, let's calculate ΔT:

ΔT = T2 - T1

ΔT = 0 - (-5.58)

ΔT = 5.58 °C

Now, let's replace in (2):

m = 5.58/1.86

m = 3 moles/kg

This is the molality of solution.

The other data of mass, can be used to calculate the molecular mass of this unknown solid, but it's not asked in the question.

Answer:

The answer is 12.35

Explanation:

From the question we are given that the concentration of [tex]H^{+}[/tex] is [tex]8.1 * 18^{-6}M[/tex]

 Generally The rate equation is given as

                                                           [tex]K_{w} = [H^{+} ][OH^{-} ][/tex]

and [tex]K_{w}[/tex] the rate constant has a value [tex]1 * 10^{-14}[/tex]

     Substituting and making [[tex]OH^{-}[/tex]] the subject we have

                                                 [tex][OH^{-} ] = \frac{1 * 10^{-14}}{[H^{+}]} = \frac{1 * 10^{-14}}{8.1 *10^{-6}} =1.235 * 10^{-9}[/tex]

                                                  [tex][OH ^ {-}] = 1.235 * 10^{-9}M[/tex]

                            Multiply the value by [tex]10^{10}[/tex] as instructed from the question we have  

                       Answer =   [tex]1.235 * 10 ^{-9} * 10^{10} = 12.35[/tex]

Hence the answer in 2 decimal places is 12.35

The concentration of OH¯ in the solution multiplied by 10¹⁰ is 12.35

The concentration of hydroxide ion [OH¯] can be obtained as follow:

K = [H⁺][OH¯]

Equilibrium constant (K) = 1×10¯¹⁴

1×10¯¹⁴ = 8.1×10¯⁶ × [OH¯]

Divide both side by 8.1×10¯⁶

[OH¯] = 1×10¯¹⁴ / 8.1×10¯⁶

[OH¯] = 1.235×10¯⁹

Multiply by 10¹⁰

[OH¯] = 1.235×10¯⁹ × 10¹⁰

[OH¯] = 12.35

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Answer:

For a: The element forming covalent compound with fluorine is Hydrogen.

For b: The electronic configuration of the element X is [tex][Uuo]8s^2[/tex]

Explanation:

Electronic configuration is defined as the representation of electrons around the nucleus of an atom.

Number of electrons in an atom is determined by the atomic number of that atom.

To write the electronic configuration of the elements in the noble gas notation, we first count the total number of electrons and then write the noble gas which lies before the same element.

For the given options:

Covalent compound is defined as the compound which is formed by the sharing of electrons between the atoms forming a compound. These are usually formed when two non-metals react.

Hydrogen is the 1st element of the periodic table and is considered as a non-metal. It has 1 unpaired electron.

Its electronic configuration is [tex]1s^1[/tex]

Fluorine is the 9th element of the periodic table. It is also a non-metal.

Its electronic configuration is [tex][He]2s^22p^5[/tex]

The two elements will share 1 electron to attain stable configuration and form HF compound.

Radium is the 88th element of the periodic table having electronic configuration of [tex][Rn]7s^2[/tex]

Let the alkaline earth metal that is not yet discovered be X

The electronic configuration of the element X is [tex][Uuo]8s^2[/tex]

The expected ground-state electron configuration for the element that forms a covalent compound with fluorine is [He]2s2p4. The electron configuration of the undiscovered alkaline earth metal after radium cannot be determined.

a) The element with one unpaired electron that forms a covalent compound with fluorine has the electron configuration of [He]2s22p4.
b) The alkaline earth metal after radium has not been discovered, so its electron configuration cannot be determined at this time.

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Answer:

The least energetic spectral line in the infrared series of the H atom is 656.1 nm

Explanation:

Photon wavelength is inversely proportional to energy. To obtain the least energetic spectral line of the hydrogen atom (H), we determine the longest wavelength possible.

[tex]\frac{1}{\lambda} = R_H[\frac{1}{n_f^2} -\frac{1}{n^2}][/tex]

Where;

nf = 2

n = 3

RH is Rydberg constant = 1.09737 × 10⁷m⁻¹

λ is the wavelength of the least energetic spectral line

Substituting the above values into the equation, we will have

[tex]\frac{1}{\lambda} = 1.09737 X 10^7[\frac{1}{2^2} -\frac{1}{3^2}][/tex]

[tex]\frac{1}{\lambda} = 1.09737 X 10^7[\frac{1}{4} -\frac{1}{9}][/tex]

[tex]\frac{1}{\lambda} = 1.09737 X 10^7[0.25 -0.1111][/tex]

[tex]\frac{1}{\lambda} = 1.09737 X 10^7[0.1389][/tex]

[tex]\frac{1}{\lambda} = 1524246.93[/tex]

[tex]\lambda} = \frac{1}{1524246.93}[/tex]

[tex]\lambda} = 6.561 X10^{-7} m[/tex]

λ = 656.1 X10⁻⁹ m

In (nm): λ = 656.1 nm

Therefore, the least energetic spectral line in the infrared series of the H atom is 656.1 nm

The wavelength of the least energetic spectral line in the infrared series of the hydrogen atom is approximately 18,400 nanometers (nm).

To find the wavelength of the least energetic spectral line in the infrared series of the hydrogen atom, we can use the Rydberg formula for the hydrogen atom:

1 / λ = R_H * (1/n₁² - 1/n₂²)

Where:

λ is the wavelength of the spectral line.

R_H is the Rydberg constant for hydrogen, approximately 1.097 x 10^7 m⁻¹.

n₁ is the principal quantum number of the initial energy level.

n₂ is the principal quantum number of the final energy level.

For the least energetic line in the infrared series, we need to consider the transition where the electron moves from a higher energy level (n₂) to a lower energy level (n₁). In this case, n₂ > n₁.

Since we are interested in the infrared series, we'll consider transitions ending in the n₁ = 3 energy level. We want the least energetic line, so we'll choose the smallest value for n₂.

Let's take n₂ = 4 and calculate:

1 / λ = 1.097 x 10^7 m⁻¹ * (1/3² - 1/4²)

1 / λ = 1.097 x 10^7 m⁻¹ * (1/9 - 1/16)

1 / λ = 1.097 x 10^7 m⁻¹ * (7/144)

Now, solve for λ:

λ = 144 / (1.097 x 10^7 m⁻¹ * 7)

λ ≈ 0.0184 meters or 18.4 millimeters

To express the wavelength in nanometers (nm), we can convert millimeters to nanometers:

λ ≈ 18.4 mm * 1,000,000 nm/mm = 18,400 nm

So, the wavelength of the least energetic spectral line in the infrared series of the hydrogen atom is approximately 18,400 nm.

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Final answer:

Two resonance forms of the triphenylmethyl cation were provided, with the positive charge located at the central carbon atom and one of the ortho positions.

Explanation:

The triphenylmethyl cation is a carbocation formed by removing an electron from the triphenylmethyl radical. It has the formula C19H16+. To write two resonance forms, we need to show the positive charge at different positions in the structure. One possible resonance form is where the positive charge is at the central carbon atom, and the other form is where the positive charge is at one of the ortho positions. The resonance structures can be represented as follows:

C6H5--C+--C6H5

:    :  

C6H4--C6H5    C6H6--C6H4