Answer:
d. Localized.
Explanation:
You posted this question in the chemistry section. The whole exercise requires you to understand the terms in a chemical context. So let's look at the three terms: homogeneous, localized, and radicalized.
Homogeneous
A chemical substance is said to be homogeneous if the chemical composition is the same throughout. It means the substance must have the same states. For example, a mixture of undiluted orange juice forms a homogeneous solution once it is diluted in water. It means that there is perfect mixing to have a uniform liquid state.
Localized
The terminology is often applied to atoms or chemical structures, particularly metals and acids. For example, atoms have localized electrons in the orbitals. It means that the electron orbits in the region for 95 % of its time. Localized means belonging to one region. This applies to the religion.
Radical
The term applies to highly reactive atomic species, normally called ions. These elements seek electrons and are highly "reactive." The ions are called radicals in this sense.
Why does the rate of a reaction generally increase with increased temperature? (Choose all that apply)
A.
at higher temperatures, molecules are more likely to collide with each other in the correct orientation.
B.
at higher temperatures, molecules will collide more often.
C.
at higher temperatures, the potential energy difference between reactants and products is smaller.
D.
at higher temperatures, more of the collisions will have the required activation energy.
Answer: Option (A) is the correct answer.
Explanation:
When we increase the temperature of a chemical reaction then molecules of the given reaction will gain kinetic energy. As a result, they will come into motion and then collide frequently with each other.
For a reaction to increase its rate it is important that the particles must collide in a correct orientation.
Thus, we can conclude that the rate of a reaction generally increase with increased temperature because at higher temperatures, molecules are more likely to collide with each other in the correct orientation.
Final answer:
The rate of a reaction increases with temperature due to more frequent collisions, collisions with greater energy exceeding the activation energy, and a higher likelihood of correct molecular orientation during these collisions.
So, correct options are A, B, and D.
Explanation:
The rate of a reaction generally increases with increased temperature for multiple reasons. At higher temperatures, molecules move more quickly which leads to an increase in the frequency of collisions between them. Furthermore, with the rise in kinetic energy, there is a greater chance that these collisions will have enough activation energy to result in a reaction. Also, as molecules move faster, they are more likely to collide in the correct orientation to instigate a reaction.
Options A and B are correct because molecules are more likely to collide and do so with the correct orientation at higher temperatures. Option D is also correct because the increase in kinetic energy means more collisions will have the required activation energy. However, Option C is not accurate because the potential energy difference between reactants and products does not depend on temperature.
27. How much energy is required to change 150.0 g of water from 10.0°C to 45.0°C? (Cwater =
4.18 J/g °C)
A. 125.43
B. 627.03
C. 219003
D. 28200 3
Answer:
The answer to your question is letter C. 21900.3. My result was 21945 J, letter C is close to this result.
Explanation:
Data
mass = 150 g
temperature 1 = T1 = 10°C
temperature 2 = T2 = 45°C
Cw = 4.18 J/g°C
Formula
Q = mCΔT = mC(T2 - T1)
Substitution
Q = (150)(4.18)(45 - 10)
Simplification
Q = (150)(4.18)(35)
Result
Q = 21945 J
The presence of many C-C and C-H bonds causes fats to be ... The presence of many C-C and C-H bonds causes fats to be ... (a) rich in energy. (b) insoluble in water. (c) low in energy. Both (a) and (b). Both (b) and (c).
Answer: Both (a) and (b)
Explanation:
Lipids are heterogeneous group of compounds of biochemical importance. Lipids may be defined as compounds which are relatively insoluble in water and are concentrated of energy source.
Fatty acids are aliphatic carboxylic acids and have the general formula, R-COOH, where COOH is the functional group and R group are hydrocarbon chain.
The structure of fat contains lot of C-C and C-H bonds and there are lot of calories, and therefore energy is packed into thier chemical structure.
Despite fat contains glycerol polar group, the long chains of hydrocarbon which are non polar makes fats insoluble in water.
Answer:
Both (a) and (b)
(a) rich in energy.
(b) insoluble in water.
Explanation:
Fats are stored as triesters (triglycerides), which when hydrolyzed form the three alcohol molecules (triglycerol) and three fatty acids. The acids that are liberated usually have long carbon chains that contain anywhere from 4 to 18 carbons. The C-C and C-H have high electron molecules present hence whey they are good sources of energy.
However, the bonding between carbon (C-C) and hydrogen (C-H) are not polar. This is because the electrons in covalent bonds are shared equally between the carbon and the hydrogen (due to their similar electronegative values) and there are no partial charges. Thus, long chains of C-C and C-H bonds form fats.
During a period of discharge of a lead-acid battery, 405 g of Pb from the anode is converted into PbSO4 (s).
What mass of PbO2 (s) is reduced at the cathode during this same period?
and
How many coulombs of electrical charge are transferred from Pb to PbO2?
Answer:
The answers to the question are as follows
First part
The mass of PbO2 (s) reduced at the cathode during the period is = 467.55_g
Second part
The electrical charge are transferred from Pb to PbO2 is 377186.86_C or 3.909 F
Explanation:
To solve this, we write the equation for the discharge of the lead acid battery as
H₂SO₄ → H⁺ + HSO₄⁻
Pb (s) + HSO⁻₄ → PbSO₄ + H⁺ + 2e⁻
at the cathode we have
PbO₂ + 3H⁺ + HSO⁻₄ + 2e⁻ → PbSO₄ + 2H₂O
Summing the two equation or the total equation for discharge is
Pb (s) + PbO₂ + 2H₂SO₄ → 2PbSO₄ + 2H₂O
From the above one mole of lead and one mole of PbO₂ are consumed simultaneously hence
Number of moles of lead contained in 405 g of Pb with molar mass = 207.2 g/mole = (405 g)/ (207.2 g/mole) = 1.95 mole of Pb
Hence number of moles of PbO₂ reduced at the cathode = 1.95 mole
mass of PbO₂ reduced at the cathode = (number of moles)×(molar mass)
= 1.95 mole × 239.2 g/mol = 467.55 g of Lead (IV) Oxide is reduced at the cathode
Part B
Each mole of Pb transfers 2e⁻ or 2 electrons, therefore 1.95 moles of Pb will transfer 2 × 1.95 = 3.909 moles of electrons transferred
Each electron carries a charge equal to -1.602 × 10⁻¹⁹ C or one mole of electrons carry a charge equal to 96,485.33 coulombs
hence 3.909 moles carries a charge = 3.909 × 96,485.33 coulombs =377186.86 Coulombs of electrical charge
or transferred electrical charge = 377186.86 C or 3.909 Faraday
Answer:
Mass of [tex]PbO_2[/tex] reduced = [tex]467g[/tex][tex]3.75*10^5C[/tex] of electrical charge is neededExplanation:
A) Moles Pb = [tex]\frac{405 g}{207.2 g/mol}[/tex]
[tex]= 1.95[/tex]
Moles Pb = moles [tex]PbO_2[/tex] reduced
Molar mass [tex]PbO_2 = 239.19 g/mol[/tex]
Grams [tex]PbO_2 = 1.95 mol * 239.19 g/mol[/tex]
[tex]= 466.42g[/tex]
B) 1 mol [tex]PbO_2[/tex] -------------------> 2 F electricity
1 .95 mol [tex]PbO_2[/tex] --------------> 2 * 1.95 F electricity = [tex]3.9F[/tex]
number of coulombs = [tex]3.9 * 96485C[/tex]
[tex]= 3.76*10^5C[/tex]
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One isotope of carbon (C) has exactly the same mass number and atomic mass since it was used as the definition of the atomic mass unit (amu). Which isotope is it and what is its atomic mass?
Answer:The isotope is Carbon-12 and its atomic mass is 12.
Explanation:
Mass number is the total number of protons and neutrons in a nucleus.
Atomic number is the number of protons in the nucleus of an atom.
An isotope of a chemical element is an atom that has a different mass number but the same atomic number as the element. The difference in mass number is from the number of neutrons (that is, a greater or lesser atomic mass) than the standard for that element.
Carbon-12 is an isotope of carbon it has 6 neutrons and 6 protons, giving it a mass number of 12 and atomic number of 6. Carbon-12 is a stable isotope of carbon, it has the same mass number and atomic number as carbon.
The isotope of carbon that has exactly the same mass and atomic number as used in the definition of the atomic mass unit is;
Isotope Carbon-12.
In chemistry, we know that;
Mass number is defined as the sum of the protons and the neutrons present in the nucleus of an atom.Meanwhile, Atomic number is defined the number of protons in the nucleus or number of electrons around the nucleus of an atom.
While an isotope is defined as an atom of an element that has the same atomic number but different mass number.
The isotope Carbon-12 is an isotope of carbon that has 6 protons and 6 neutrons.This means from the definition of mass number; Carbon-12 will have a mass number = 6 + 6 = 12Number of protons = number of electrons. Thus, number of electrons = 6 and therefore, atomic number = 6. From periodic table, the element Carbon has the same mass number and atomic number as its' isotope carbon-12.
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A 222 N force is required to keep an object moving along a circular path with a diameter of 11.6 m at a speed of 7.60 m/s. What is the mass of the object?
Answer:
[tex]m=22.3\ kg[/tex]
Explanation:
The expression for centrifugal force is shown below as:-
[tex]F=\frac{m\times v^2}{r}[/tex]
Where, m is the mass of the object = ?
v is the velocity of the object = 7.60 m/s
r is the radius
F is the force = 222 N
Diamter = 11.6 m
Radius = d/2 = 11.6 m/2 = 5.8 m
Applying the values in the above expression as:-
[tex]222=\frac{m\times {7.60}^2}{5.8}[/tex]
[tex]57.76m=1287.6[/tex]
[tex]m=22.3\ kg[/tex]
The freezing temperatures for water for Celsius and Fahrenheit scales are 0ºC and 32ºF. The boiling temperatures for water are 100 ºC and 212 ºF. Let C denote the temperature in Celsius and F in Fahrenheit. Write the conversion function from Celsius to Fahrenheit. Use the function to convert 25 ºC into ºF.
Answer:
Therefore the required function is
[tex]C= \frac{5}{9} (F-32)[/tex]
Therefore 25°C=57°F
Explanation:
F denotes temperature of Fahrenheit and C denotes temperature of Celsius.
[tex]\frac{C-0}{100-0} =\frac{F-32}{212-32}[/tex]
[tex]\Rightarrow C= \frac{100}{180} (F-32)[/tex]
[tex]\Rightarrow C= \frac{5}{9} (F-32)[/tex]
Therefore the required function is
[tex]C= \frac{5}{9} (F-32)[/tex]
Putting C=25°C in above equation
[tex]25=\frac{5}{9} (F-32)[/tex]
[tex]\Rightarrow 25 \times \frac{9}{5} = F-32[/tex]
⇒45 =F-32
⇒F=32+45
⇒F=57
Therefore 25°C=57°F
The conversion function from Celsius to Fahrenheit is F = (C × 9/5) + 32. Using this, 25°C is converted to 77°F.
The subject of this question is temperature conversion between Celsius and Fahrenheit scales. To create a conversion function from Celsius to Fahrenheit, we use the relationship that a change of 1°C is equivalent to a change of 1.8°F. Since the freezing point of water is 0°C and 32°F, we can derive the following function for converting temperature from Celsius to Fahrenheit:
F = (C × 9/5) + 32.
Using this function, we can convert 25°C into Fahrenheit as follows:
Multiply the Celsius temperature by 9/5: 25 × 9/5 = 45.Add 32 to the result: 45 + 32 = 77.Therefore, 25°C is equal to 77°F.
A scientist wants to perform a test that will indicate whether a nucleic acid sample is composed of RNA or DNA. Testing for the presence of which of the following is most appropriate in this situation?Answer1. thymine2. guanine3. phosphate4. uracil5. nitrogen
Answer:
The correct answer is 1 and 4, thus
Testing for the presence of 1. Thymine (DNA) and 4. Uracil (RNA)
Explanation:
DNA and RNA differ in the composition of their nucleotides in that one of their four nucleotide organic bases differs in the two polymers. While bases adenine, guanine, and cytosine are present in RNA and DNA; only DNA contains thymine DNA, and only RNA contains uracil. These components, Adenine, Guanine, Thymine, Uracil and Cytosine are abbreviated as A, G, T, U, and C, respectively. Their acronyms above are used to represent long complexes formed by these bases.
To differentiate between RNA and DNA, test for uracil, which indicates RNA, as thymine is present in DNA but not in RNA. This test is feasible due to the exclusive presence of uracil in RNA.
Explanation:To determine whether a nucleic acid sample is composed of RNA or DNA, testing for the presence of uracil is most appropriate. DNA contains the nitrogenous bases adenine (A), cytosine (C), guanine (G), and thymine (T), while RNA contains adenine, cytosine, guanine, and uracil (U) instead of thymine. Therefore, the presence of uracil would indicate the sample is RNA, while the presence of thymine would suggest it is DNA. This is because uracil is exclusive to RNA, and thymine is exclusive to DNA.
Other differences between DNA and RNA include the sugar present in their nucleotides; DNA contains deoxyribose while RNA contains ribose. This distinction, however, is not typically tested for since it is more challenging to do without specialized equipment.
A hot metal plate at 150°C has been placed in air at room temperature. Which event would most likely take place over the next few minutes?
A. Molecules in both the metal and the surrounding air will start moving at lower speeds.
B. Molecules in both the metal and the surrounding air will start moving at higher speeds.
C. The air molecules that are surrounding the metal will slow down, and the molecules in the metal will speed up.
D. The air molecules that are surrounding the metal will speed up, and the molecules in the metal will s
Answer:
The air molecules that are surrounding the metal will speed up, and the molecules in the metal will slow down.
Explanation:
The hot metal at 150 °C loses heat energy by conduction to the surrounding air molecukes and as such cools down, the cooler metal consists of lesser enery to power the movement of the molecules of the metal hence the metal molecules slows down in their movement as seen in the equation of heat and temperature
ΔH = m×C×ΔT where ΔH is the change in heat energy (heat loss of the metal, C is the heat capacity and ΔT is the temperature change
For the surrounding air that experiences increase in temperature the same process follows leading to increase in the kinetic energy of the air molecules and decrease in kinetic energy of the metal molecules as shown in the formula
K = [tex]\frac{3}{2}[/tex]×[tex]\frac{R}{N_{A} }[/tex]×T where K = Kinetic Energy, R = gas constant (8.314J/mol×K) and [tex]N_{A}[/tex] = Avogadros number (6.022×[tex]10^{23}[/tex] atoms/mol)
Answer:
d
Explanation:
What is the sound intensity level in decibels of ultrasound of intensity 7.53 ✕ 104 W/m2, used to pulverize tissue during surgery?
Answer : The intensity of sound level in decibels is, 169 dB
Explanation:
The expression used for the intensity of sound level is given by the equation:
[tex]P=10\times \log \frac{I}{I_o}[/tex]
where,
I = final intensity = [tex]7.53\times 10^4W/m^2[/tex]
[tex]I_o[/tex] = initial intensity = threshold intensity of human hearing = [tex]10^{-12}W/m^2[/tex]
Now put all the given values in the above formula, we get:
[tex]P=10\times \log \frac{7.53\times 10^4W/m^2}{10^{-12}W/m^2}[/tex]
[tex]P=168.767dB\approx 169dB[/tex]
Thus, the intensity of sound level in decibels is, 169 dB
Final answer:
The sound intensity level in decibels of the ultrasound used to pulverize tissue during surgery is 160 dB.
Explanation:
The sound intensity level in decibels (dB) of ultrasound with an intensity of 7.53 × 10^4 W/m² used to pulverize tissue during surgery can be calculated using the formula:
IdB = 10 log10 (I/I0)
where I is the given intensity (7.53 × 10^4 W/m²) and I0 is the reference intensity (10^-12 W/m²).
Using the formula:
IdB = 10 log10 (7.53 × 10^4 / 10^-12)
We can calculate:
IdB = 10 log10 (7.53 × 10^16)
IdB = 10 × 16 (using log10 (ab) = b × log10 (a))
IdB = 160 dB
Therefore, the sound intensity level in decibels of the given ultrasound is 160 dB.
Some friends are trying to make wine in their basement. They've added yeast to a sweet grape juice mixture and have allowed the yeast to grow. After several days they find that sugar levels in the grape juice have dropped, but there's no alcohol in the mixture. The most likely explanation is that ______.
Answer:
The yeast respired aerobically
Explanation:
The expectation here was that the yeast was going to put the sugar in the grape juice through fermentation, which is an anaerobic process that results in alcohol as one of the products. However since no alcohol was found in this particular example, it is fair to assume that maybe there was oxygen in teh muxture and therefore the yeast respired aerobically, producing water and carbon dioxide as products.
Olympic cyclists fill their tires with helium to make them lighter. Assume that the volume of the tire is 860 mL , that it is filled to a total pressure of 120 psi , and that the temperature is 26°C. Also, assume an average molar mass for air of 28.8 g/mol.
Calculate the mass of air in an air filled tire.
Calculate the mas of helium in a helium-filled tire.
What is the mass difference between the two?
Answer:
The mass of air is 8.245 g
The mass of helium is 1.145 g
The difference is 7.1 g
Explanation:
Total mass (air and helium) = PVM/RT
P is total pressure in the tire = 120 Psi = 120/14.696 = 8.17 atm
V is volume of the tire = 860 mL = 860 cm^3
M is the total molar mass of air and helium = 28.8 + 4= 32.8 g/mol
R is gas constant = 82.057 cm^3.atm/mol.K
T is temperature = 26°C = 26+273 = 299 K
Total mass = 8.17×860×32.8/82.057×299 = 9.39 g
Mass of air = mass fraction of air × total mass = 28.8/32.8 × 9.39 = 8.245 g
Mass of helium = total mass - mass of air = 9.39 - 8.245 = 1.145 g
Difference = 8.245 - 1.145 = 7.1 g
To calculate the mass of air in an air-filled tire, you can use the ideal gas law equation PV = nRT. The mass of air in the tire is 142.57 g. To calculate the mass of helium in a helium-filled tire, use the same equation and the molar mass of helium. The mass of helium in the tire is 19.84 g. The mass difference between the two is -122.73 g, indicating that the helium-filled tire is lighter than the air-filled tire.
Explanation:To calculate the mass of air in an air-filled tire, we can use the ideal gas law equation PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature in Kelvin.
First, we need to convert the volume from mL to L and the temperature from Celsius to Kelvin. So, the volume is 0.860 L, and the temperature is 26 + 273 = 299 K.
Next, we rearrange the ideal gas law equation to solve for n, the number of moles: n = PV / RT. Substituting the values, we get n = (120 psi x 0.860 L) / (0.0821 L.atm/mol.K x 299 K) = 4.96 moles.
The molar mass of air is given as 28.8 g/mol, so the mass of air in the tire is 4.96 moles x 28.8 g/mol = 142.57 g.
To calculate the mass of helium in a helium-filled tire, we can follow the same steps as above, but use the molar mass of helium (4 g/mol) instead. Substituting the values, we get n = (120 psi x 0.860 L) / (0.0821 L.atm/mol.K x 299 K) = 4.96 moles.
So, the mass of helium in the tire is 4.96 moles x 4 g/mol = 19.84 g.
To find the mass difference between the two, we subtract the mass of air from the mass of helium: 19.84 g - 142.57 g = -122.73 g. The negative sign indicates that the helium-filled tire is lighter than the air-filled tire by 122.73 g.
A 36.2 g object has a heat capacity of 12.5 J/ oC. How much energy (in J) is required to raise the temperature by 5.73 oC?
Answer:
[tex]\Delta H=2592.825\ J[/tex]
Explanation:
The expression for the calculation of the enthalpy change of a process is shown below as:-
[tex]\Delta H=m\times C\times \Delta T[/tex]
Where,
[tex]\Delta H[/tex] is the enthalpy change
m is the mass
C is the specific heat capacity
[tex]\Delta T[/tex] is the temperature change
Thus, given that:-
Mass of object = 36.2 g
Specific heat = 12.5 J/g°C
[tex]\Delta T=5.73\ ^0C[/tex]
So,
[tex]\Delta H=36.2\times 12.5\times 5.73\ J=2592.825\ J[/tex]
[tex]\Delta H=2592.825\ J[/tex]
Answer:71.625J
Explanation:Energy(Q)=mCpT
But recall that they said heat capacity (C), not specific heat capacity(cp)....Heat capacity=Mass *cp,but the heat capacity was clearly given so the mass is irrelevant in this case.
Energy (Q)=Heat capacity*Temperature change
Energy=12.5*5.73=71.625J
A tank of methane gas contains 2.8 m³ of the gas at 20°C. The tank has a pressure-release valve that releases gas into a secondary tank that will hold 0.2m³ of gas if the pressure rises.
At what Celsius temperature will the methane fill both tanks?
Answer:
The answer to your question is T2 = 20.93°K
Explanation:
Data
Volume 1 = V1 = 2.8 m³
Temperature 1 = T1 = 20°C
Volume 2 = V2 = 0.2 m³
Temperature 2 = T2 = ?
Process
To solve this problem use Charles' law
[tex]\frac{V1}{T1} = \frac{V2}{T2}[/tex]
Solve for T2
T2 = [tex]\frac{T1V2}{V1}[/tex]
1.- Convert temperature to °K
T1 = 20 + 273 = 293°K
2.- Substitute values
T2 = [tex]\frac{(293)(0.2)}{2.8}[/tex]
3.- Simplify
T2 = [tex]\frac{58.6}{2.8}[/tex]
4.- Result
T2 = 20.92°K
Final answer:
The question seeks the temperature at which methane gas, initially at 2.8 m³ and 20°C, will expand to fill an additional 0.2 m³ tank, by applying Charles's Law to relate volume and temperature of a gas under constant pressure.
Explanation:
The question, "At what Celsius temperature will the methane fill both tanks?", involves understanding the principles of gas laws, specifically Charles's Law which relates volume and temperature of a gas at constant pressure. Given the initial volume of methane gas is 2.8 m³ at 20°C, and it will be released into a secondary tank of volume 0.2 m³ if the pressure increases, we're essentially looking for the temperature at which the total volume of 3.0 m³ (2.8 m³ + 0.2 m³) is achieved at constant pressure.
Charles's Law states that V1/T1 = V2/T2, where V refers to volume and T refers to temperature in Kelvin. To find the desired temperature, we first convert the initial temperature to Kelvin (20°C + 273.15 = 293.15 K), then solve for T2 while using the total volume as V2. Without going into the numerical solving part (since the specific question doesn't require it), the concept demonstrates the application of Charles's Law in determining the temperature that leads to the expansion of methane gas to fill both tanks.
The volume of a gas is reduced from 4 L to 0.5 L while the temperature is held constant. How does the gas pressure change?
It increases by a factor of two.
It increases by a factor of eight.
It decreases by a factor of eight.
It increases by a factor of four.
Answer:
It increases by a factor of eight
Explanation:
When temperature is held constant, gas pressure changes according the volume, in undirectly proportion.
Volume increases → Pressure decreases
Volume decreases → Pressure increases
As volume gas, was reducted from 4L to 0.5L, it was reduced by 1/8, so the pressure gas was increased by a factor of eight.
Answer:
It increases by a factor of eight.
Explanation:
Which anthropogenic pollutants are implicated in the formation of most acidic precipitation? 1. carbon oxides 2. ozone and carbon monoxide 3. phosphoric acid and hydrochloric acid 4. nitrogen oxides and sulfur oxides
Answer:
nitrogen oxides and sulphur oxides
Explanation:
Factors responsible for antropogenic pollution are:
burning of fossil fuels deforestation mining sewage industrial effluent pesticides, fertilizers, etc.The primary air pollutants released from burning of fossil fuels are oxides of nitrogen, sulfur oxides and carbon monoxide.
Out of which the main pollutants that are responsible for acidic precipitation are oxides of nitrogen and sulfur oxides.
Sulfur oxides and Oxides of nitrogen reacts with moisture present in the air to form sulfuric acid and nitric acid respectively.
These acids get mixed with rain and cause acidic precipitation.
Therefore, the correct option is oxides of nitrogen and sulfur oxides.
When DNA is replicated, it is necessary for the two strands to "unzip" temporarily. Choose which bonding type is most appropriate for holding the strands together in this way.
A) ionic bonding
B) hydrogen bonding
C) non-polar covalent bonding D) polar covalent bonding
Answer: B) hydrogen bonding
Explanation:
A) An ionic bond is formed when an element completely transfers its valence electron to another element.
B) Hydrogen bonds are special type of dipole dipole forces which are formed when hydrogen bonds with an electronegative element.
DNA strands are held together by hydrogen bonds between the bases on one strand and those on the other. Adenine and thymine have two hydrogen bonds between them while cytosine and guanine have three hydrogen bonds between them.
C) Non-polar covalent bond is defined as the bond which is formed when there is no difference of electronegativities between the atoms.
D) A polar covalent bond is defined as the bond which is formed when there is a difference of electronegativities between the atoms.
When DNA is replicated, the two strands unzip temporarily. The strands are held together by hydrogen bonding.
Explanation:When DNA is replicated, the two strands temporarily unzip or separate from each other. The type of bonding that holds the strands together is hydrogen bonding. Hydrogen bonding occurs between the nitrogenous bases of the DNA strands.
These bases, adenine (A), thymine (T), cytosine (C), and guanine (G), form complementary base pairs with each other, with adenine pairing with thymine and cytosine pairing with guanine.
The hydrogen bonds between these base pairs keep the two DNA strands connected.
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A 2.12-g sample of scandium metal is reacted with excess hydrochloric acid to produce 0.1415 g hydrogen gas. What is the formula of the scandium chloride produced in the reaction?
Answer:
The formula of the scandium chloride produced in the reaction is ScCL₃
Explanation:
With the given data, you can know the molar relationship between Sc and H₂ (molar ratio) to determine the reaction stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction).
Then: [tex]molar ratio=\frac{moles Sc}{moles H_{2} }[/tex]
Knowing that:
mass Sc= 2.12 gmolar mass of Sc= 44.956 g/molmass H₂= 0.1415 gmolar mass of H₂= 2 g/moland knowing that the number of moles (n) of a compound can be calculated as: [tex]n=\frac{mass}{molar mass}[/tex]
Then:
[tex]n (Sc)=\frac{2.12g}{44.956\frac{g}{mol} }[/tex] then [tex]n (Sc)=0.047 moles[/tex][tex]n(H_{2} )=\frac{0.1415g}{2\frac{g}{mol} }[/tex] then [tex]n(H_{2} )=0.071 moles[/tex]So:
[tex]molarratio=\frac{0.047}{0.071}[/tex]
Then it is possible to say that the molar ratio is approximately equal to [tex]\frac{2}{3}[/tex]. This indicates that by stoichiometry 2 moles of Sc are needed to produce 3 moles of H₂.
So:
2 Sc + HCl → ScCL₃ + 3 H₂
The law of conservation of matter states that since no atom can be created or destroyed in a chemical reaction, the number of atoms that are present in the reagents has to be equal to the number of atoms present in the products.
Then, balancing the equation so that the same amount of moles of each element on each side of the equation is obtained:
2 Sc + 6 HCl → 2 ScCL₃ + 3 H₂
The formula of the scandium chloride produced in the reaction is ScCL₃
what events and experiences lead bruno to gradually give up some of his innocence and see things differently
Answer:
The events of Bruno seeing the young boy in the concentration camp, slowly seeing his father’s evil side come out, and having his sister explain to him what was really happening; all lead Bruno to gradually see what was really going on.
Explanation:
Use the drop-down menus to match each part of the scenario to the correct scientific practice. Akira records the speed of a reaction, first without a catalyst, and then with a catalyst. Akira creates a reaction without a catalyst, then repeats the reaction with a catalyst. Akira turns in a written lab report to his science teacher. Akira wonders, "Will adding a catalyst speed up this chemical reaction?" Akira writes in his notes that adding a catalyst sped up the chemical reaction because the catalyst lowered the activation energy needed to start the reaction.
Answer:
1)collecting data
2)performing an investigation
3)communicating results
4)asking a question
5)providing explanation
Explanation:
Scenario 1 is matched with collecting data. Scenario 2 is matched with performing an investigation. Scenario 3 is matched with communicating results. Scenario 4 is matched with asking a question. Scenario 5 is matched with providing explanation for the given scientific practice using catalyst.
A catalyst is a material that speeds up a chemical reaction without being consumed or irreversibly transformed in the process. It promotes the process by giving a lower activation energy alternate reaction pathway. The activation energy is the smallest amount of energy required for a chemical reaction to take place. A catalyst permits the reaction to occur more rapidly and efficiently by decreasing the energy barrier.
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When you heat an air-filled balloon, what happens inside with regard to the movement of air molecules?
What is the rms speed of cesium atoms that have been cooled to a temperature of 100 nk?
Answer : The root mean square speed is, [tex]4.33\times 10^{-3}m/s[/tex]
Explanation :
The formula used for root mean square speed is:
[tex]\nu_{rms}=\sqrt{\frac{3kN_AT}{M}}[/tex]
where,
[tex]\nu_{rms}[/tex] = root mean square speed
k = Boltzmann’s constant = [tex]1.38\times 10^{-23}J/K[/tex]
T = temperature = 100 nK = [tex]100\times 10^{-9}K[/tex]
M = atomic mass of cesium = 132.91 g/mole = 0.13291 kg/mole
[tex]N_A[/tex] = Avogadro’s number = [tex]6.02\times 10^{23}mol^{-1}[/tex]
Now put all the given values in the above root mean square speed formula, we get:
[tex]\nu_{rms}=\sqrt{\frac{3\times (1.38\times 10^{-23}J/K)\times (6.02\times 10^{23}mol^{-1})\times (100\times 10^{-9}K)}{0.13291kg/mole}}[/tex]
[tex]\nu_{rms}=4.33\times 10^{-3}m/s[/tex]
Thus, the root mean square speed is, [tex]4.33\times 10^{-3}m/s[/tex]
The rms speed of cesium atoms at 100 nk can be estimated using the formula for the root mean square speed, which involves the temperature and mass of the cesium atom. However, at such low temperatures, quantum mechanical effects become important, and the classical formula may not provide an accurate result.
Explanation:The question you've asked about the rms (root mean square) speed of cesium atoms cooled to a temperature of 100 nanokelvins (nk) involves a calculation based on the kinetic molecular theory of gases. The rms speed of the atoms in a gas can be found using the formula:
[tex]\(v_{rms} = \sqrt{\frac{3kT}{m}}\)[/tex]
where:
\(v_{rms}\) is the root mean square speed\(k\) is the Boltzmann constant [tex]\(1.38 \times 10^{-23} J/K\)[/tex]\(T\) is the temperature in kelvins\(m\) is the mass of one atom/molecule of the gasSince cesium atoms are cooled to 100 nk, we can assume this is much lower than room temperature and requires quantum mechanical considerations for a precise answer. In ultra-cold conditions such as these, traditional formulas based on classical physics may not be sufficient, and one usually has to consider quantum mechanical effects. However, if we continue with the classical approach, you would need the mass of a cesium atom to calculate the rms speed.
For educational purposes, to calculate this, you need the mass of a cesium atom in kilograms and plug the values into the formula to get [tex]\(v_{rms}\)[/tex]ind that the temperature provided must be converted into kelvins, but since nanokelvins are already a Kelvin measurement, no conversion is needed. Be aware that the classical formula may not hold true at such low temperatures due to quantum effects.
Manganese sulfate forms a pale pink hydrate with the formula MnSO 4 ⋅ n H 2 O ( s ) . If this hydrate is heated to a high enough temperature, H 2 O ( g ) can be driven off, leaving the grey‑white anhydrous salt MnSO 4 ( s ) . A 16.260 g sample of the hydrate was heated to 300 ∘ C . The resulting MnSO 4 ( s ) had a mass of 14.527 g . Calculate the value of n in MnSO 4 ⋅ n H 2 O ( s ) .
Answer:
Value of n in MnSO₄.nH₂O is one.
Explanation:
The n represents the number of moles of water attached to the formula unit manganese sulfate. These moles (n) can be determined by taking the ratio of the moles of anhydrous salt and the moles of water. The moles of water can be determined by taking the difference of final and initial mass of the salt. This difference is equal to the mass of the water, mathematically it can be represented as,
Mass of H₂O = initial mass of the salt (g) - final mass of the salt (g)
Mass of H₂O = 16.260 g - 14.527 g
Mass of H₂O = 1.733 g
moles of H₂O = (1.733 g) ÷ (18.015 g/mole)
moles of H₂O = 0.0962
For the moles of anhydrous salt:
moles of MnSO₄ = mass of MnSO₄ ÷ molar mass of MnSO₄
moles of MnSO₄ = 14.5277 ÷ 151.001
moles of MnSO₄= 0.0962
Now for n:
n = moles of water ÷ moles of MnSO₄
n = 0.0962 ÷ 0.0962
n = 1
The above calculations show that one mole of H₂O is attached to the one formula unit of MnSO₄
Final answer:
To calculate the value of n in the hydrate formula MnSO₄ .nH₂O, the mass of water driven off by heating is found to be 1.733 g. This corresponds to 0.0962 mol of water. Since the ratio of water to MnSO₄is 1:1, n is determined to be 1.
Explanation:
To calculate the value of n in the hydrate formula MnSO₄ . H₂O, we need to find the number of moles of water lost upon heating. We subtract the mass of the anhydrous salt (14.527 g) from the original mass of the hydrate (16.260 g) to get the mass of water lost:
Mass of H₂O = 16.260 g - 14.527 g = 1.733 g
Next, we calculate the number of moles of water using its molar mass (18.015 g/mol):
Number of moles of H₂O = 1.733 g / 18.015 g/mol ≈ 0.0962 mol
To find the number of moles of MnSO₄ in the anhydrous sample, we need its molar mass, which is approximately 151.00 g/mol for MnSO₄. Using the mass of the anhydrous salt:
Number of moles of MnSO₄ = 14.527 g / 151.00 g/mol ≈ 0.0962 mol
This indicates that the mole ratio of H₂O to MnSO₄ is 1:1. Therefore, the value of n is 1, and the hydrate is MnSO₄.H₂O.
What is the [HPO42-]/[H2PO4-] ratio in an acetate buffer at pH 7.20? (The pKa for dihydrogenphosphate is 7.10.)
Answer:
[tex]\frac{[HPO_4^{2-}]}{[H_2PO_4^{-}]}=1.26[/tex]
Explanation:
Considering the Henderson- Hasselbalch equation for the calculation of the pH of the buffer solution as:
pH=pKa+log[base]/[acid]
For the equilibrium buffer of dihydrogen phosphate, pKa = 7.10
pH = 7.20
[tex]pH=pKa+\log\frac{[base]}{[acid]}[/tex]
[tex]7.20=7.10+\log\frac{[HPO_4^{2-}]}{[H_2PO_4^{-}]}[/tex]
[tex]\log\frac{[HPO_4^{2-}]}{[H_2PO_4^{-}]}=0.10[/tex]
[tex]\frac{[HPO_4^{2-}]}{[H_2PO_4^{-}]}=1.26[/tex]
The [HPO42-]/[H2PO4-] ratio in an acetate buffer at pH 7.20 is approximately 1.26, calculated using the equation pH = pKa + log ([A-]/[HA]) and the provided pKa for dihydrogenphosphate.
Explanation:To calculate the [HPO42-]/[H2PO4-] ratio in an acetate buffer at pH 7.20, we can use the equation pH = pKa + log ([A-]/[HA]). In this case, the pKa for dihydrogenphosphate is 7.10. Given that pH = 7.20, we can rewrite this as log ([HPO42-]/[H2PO4-]) = pH - pKa = 7.20 - 7.10 = 0.1. The anti-logarithm of 0.1 gives us around 1.26. Therefore, the [HPO42-]/[H2PO4-] ratio is approximately 1.26.
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: How does the solubility of a solid in a liquid depend on temperature? How is this temperature dependence exploited to purify solids through recrystallization?
Answer:
Explanation:
Solubility of many solid in a solvent increases with increase in temperature. Increase in temperature increases kinetic energy of the solute, increasing collision and weakens the intermolecular force within the solute. This makes the solute dissolve faster in their solvents.
During recrystallization, more solutes are added to the solvent at higher temperature so that a supersaturated solution is produced on cooling. As the solution cools the over saturated solute begins to precipitate out of the solution.
Recrystallization is a form of purification if solid, as the crystalline solids continue to precipitate it reject impurities are comes out as a purer solid
The gas in a 600. mL balloon has a pressure of 1.20 atm. If the temperature remains constant, what will be the pressure of the gas in the balloon when it is compressed to 400. mL?
Answer:
1.8 atm
Explanation:
As temperature and moles of a gas reamin both constant, we can say that:
Pressure₁ . Volume₁ = Pressure₂ . Volume₂
1.20 atm . 600 mL = Pressure₂ . 400 mL
(1.20 atm . 600 mL) / 400 mL = Pressure ₂ → 1.8 atm
Given a sorted list of 1024 elements, what is the runtime for binary search if the search key is less than all elements in the list?
Answer: 1024
Linear search's runtime is proportional to the number of list elements.
If a piece of ice weighs 36.0 NN at the surface of the earth, what is its mass on the earth's surface?
Answer:
3.67 kilograms is the mass of a given ice on the earth's surface.
Explanation:
Weight of an object is the force acting on an object by virtue of its mass.
Weight(W)=[tex]mass(m)\times acceleration(a)[/tex]
We have :
Mass of an ice = m =?
Acceleration due to gravity ,a = [tex]9.8m/s^2[/tex]
Weight of an ice , W= 36.0 N
Putting in the values we get,
[tex]36.0 N=m\times 9.8 g/m^2[/tex]
[tex]m=\frac{36.0 N}{9.8 m/s^2}=3.67 kg[/tex]
3.67 kilograms is the mass of a given ice on the earth's surface.
Which of the following statements about acids/bases is correct: Group of answer choices
1. molecule with a pH of 9 has a higherA concentration of H than water
2. A molecule with a pH of 10 has a higher concentration of OH- than water
3. A molecule with a pH of 12 has a lower concentration of OH- than water
4. A molecule with a pH of 4 has a higher concentration of OH- than water
Answer:
2
Explanation:
To answer this correctly, we need to make a reference to the pH scale. Here we know that pH 1-6 stands for acidity where the smaller the value, the higher the concentration of H3O+ and the higher the acidity. Also, pH 7 stands for neutral, there is an interpreted balance here, where the concentrations are averagely equal. Also , we have pH 8 to 14 where we have the alkalinity, the higher the value the higher the concentration of OH-.
Now let’s solve the question at hand.
1 is wrong
Water is termed neutral with an average balance of the two ions. pH 9 means higher OH- which stipulates lesser H+ than water.
2 is correct
The pH is termed alkaline and has more hydroxide concentration than water.
3 is wrong
It should have a higher concentration of OH- than water
4 is wrong
It should have a higher acidity and lesser alkalinity. This translates to higher H+ and lower OH- relative to water
We expect the enthalpy of cumbustion of two isomers to be _________. The molecular formulas of two molecules are _____, so the balanced chemical equation for the two combustion reactions are________, in calculation of combustion enthalpy from _____ of products and reactants, the difference will be in the ______of the two_____
Different, Isomers, standard enthalpies of formation, combustion products, standard enthalpies of combustion, the same, very similar
The rod-shaped n-pentane has ________ possible________ than the almost________ neopentane
Tetrahedral, less, vibrational and rotational motions, more, translational motion, spherical
Final answer:
The enthalpy of combustion of two isomers with the same molecular formula will be different due to their different structural arrangements. The rod-shaped n-pentane has less possible vibrational and rotational motions compared to the almost spherical neopentane.
Explanation:
The enthalpy of combustion of two isomers with the same molecular formula will be different. Isomers are compounds that have the same molecular formula but different structural arrangements. For example, the isomers of C4H10 are n-butane and isobutane. The balanced chemical equations for their combustion reactions are:
n-Butane: C4H10 + 6.5O2 → 4CO2 + 5H2O
Isobutane: C4H10 + 6.5O2 → 4CO2 + 5H2O
When calculating the combustion enthalpy from the standard enthalpies of formation of products and reactants, the difference in enthalpy will be due to the different standard enthalpies of combustion of the two isomers.
The rod-shaped n-pentane has less possible vibrational and rotational motions than the almost spherical neopentane. This is because neopentane is a more compact, three-dimensional molecule, while n-pentane is a linear molecule. Linear molecules have fewer degrees of freedom and therefore have fewer potential vibrational and rotational motions compared to more complex, three-dimensional molecules like neopentane.
The enthalpies of combustion for isomers are different due to structural variations. N-pentane has more vibrational and rotational motions compared to neopentane.
'We expect the enthalpy of combustion of two isomers to be different. The molecular formulas of two molecules are isomers, so the balanced chemical equations for the two combustion reactions are very similar. In calculation of combustion enthalpy from standard enthalpies of formation of products and reactants, the difference will be in the standard enthalpies of combustion of the two molecules.'
The rod-shaped n-pentane has more possible vibrational and rotational motions than the almost spherical neopentane.