Question 1

How much H₂ (in liters) is produced at 65°C and 670. torr by the reaction of 75.7 g of zinc? Zn(s) + 2 H+(aq) → Zn₂+(aq) + H₂(g)

Accepted Answer

The answer of How much H₂ (in liters) is produced...

Question 2

Give the molecular shape of NO₃^-.

Accepted Answer

The nitrate ion (NO3-) has a trigonal planar molecular shape due to the resonance of the three equivalent N-O bonds.

Question 3

Write a balanced half equation for the following couple: NO₃^- | NH₄⁺(acidic)

Accepted Answer

The balanced half-equation in acidic solution involves adding protons and electrons to balance the charge and mass, resulting in NO₃⁻ + 10 H⁺ + 8 e⁻ → NH₄⁺ + 3 H₂O.

Question 4

Pyrosulfuric is also called disulfuric H₂S2O₇. Pyrosulfuric acid may be synthesized by dissolving SO₃ in ________.

Accepted Answer

Pyrosulfuric acid (H2S2O7) is formed by dissolving sulfur trioxide (SO3) in sulfuric acid (H2SO4).

Question 5

How much H₂ (in liters) is produced at 45 °C and 770. torr by the reaction of 45.7 g of zinc? Zn(s) + 2 H+(aq) → Zn₂+(aq) + H₂(g)

Accepted Answer

1. Write the balanced chemical equation: Zn(s) + 2 H+(aq) → Zn₂+(aq) + H₂(g) 2. Convert the mass of Zn to moles: 45.7 g Zn / 65.38 g/mol Zn = 0.699 moles Zn 3. Use stoichiometry to find the moles of H₂ produced: Since the stoichiometry of the reaction is 1:1 for Zn and H₂, we can see that 0.699 moles of H₂ will be produced. 4. Use the ideal gas law to find the volume of H₂: PV = nRT where P = pressure in atm, V = volume in L, n = moles, R = gas constant (0.0821 L atm/mol K), and T = temperature in K (convert °C to K by adding 273): P = 770 torr / 760 torr/atm = 1.01 atm T = 45 °C + 273 = 318 K V = nRT/P = (0.699 mol)(0.0821 L atm/mol K)(318 K)/(1.01 atm) = 18.0 L Therefore, the answer is C) 18.0 L.

Question 6

Give the molecular shape of SO₄^2-.

Accepted Answer

The molecule has 1 sulfur atom as the central atom bonded to 4 oxygen atoms and 1 phosphorus atom. This arrangement results in a tetrahedral shape with bond angles of approximately 109.5 degrees.

Question 7

Give the molecular shape of SO₂.

Accepted Answer

SO₂ has five atoms bonded to the central atom, which is sulfur (S). This means that the molecule is likely to have a trigonal bipyramidal electron geometry. However, two of the five atoms are lone pairs, which repel the bonded atoms and distort the shape of the molecule. The result is a bent molecular geometry, with a bond angle of less than 120 degrees. Therefore, the best choice for the molecular shape of SO₂ is E) bent.

Question 8

Write a balanced half equation for the following couple: SO₄^2- | S (acidic)

Accepted Answer

The balanced half equation in acidic conditions is SO₄²⁻ + 8 H⁺ + 6 e⁻ → S + 4 H₂O.

Question 9

One of the natural processes that destroys ozone in the atmosphere is postulated to consist of two steps: O₃(g) + UV radiation → O₂(g) + O(g) O₃(g) + O(g) → 2 O₂(g) The standard enthalpies of formation for ozone and for atomic oxygen are +142.7 kJ/mol and +249.2 kJ/mol, respectively. What would be the standard energy change associated with the combination of ozone and atomic oxygen to form 50.0 L of molecular oxygen, measured at -75°C and 0.12 atm?

Accepted Answer

The reaction O₃(g) + O(g) → 2 O₂(g) has a standard enthalpy change of -106.5 kJ/mol. Using the ideal gas law, 50.0 L of O₂ at -75°C and 0.12 atm corresponds to 0.107 mol of O₂. The energy change is then -106.5 kJ/mol * 0.107 mol = -11.4 kJ. Since the reaction produces 2 moles of O₂, the energy change for 1 mole of O₂ is -72 kJ.

Question 10

How much hydrogen (in liters at STP) is required to change 857 kg of diisobutylene to isooctane? Molar mass of diisobutylene is 112.2 grams. CH₃C(CH₃)₂CH=C(CH₃)₂ + H₂ → CH₃C(CH₃)₂CH₂CH(CH₃)₂

Accepted Answer

First, we need to calculate the number of moles of diisobutylene.
857 kg of diisobutylene = 857000 g / 112.2 g/mol = 7646.17 mol
According to the balanced chemical equation, one mole of diisobutylene reacts with one mole of hydrogen to produce one mole of isooctane.
So, we need 7646.17 mol of hydrogen.
Now we can use the ideal gas law to calculate the volume of hydrogen at STP (standard temperature and pressure).
PV = nRT
STP conditions: 
P = 1 atm 
V = ? 
n = 7646.17 mol 
R = 0.08206 L•atm/mol•K 
T = 273.15 K 
Solving for V: 
V = (nRT)/P 
V = (7646.17 mol)(0.08206 L•atm/mol•K)(273.15 K)/(1 atm) 
V = 1.71 × 10^5 L or 1.71 × 10^15 mL or 1.71 × 10^12 cm^3 
Converting to liters and rounding to two significant figures, we get 1.7 × 10^15 L which is equivalent to 1.71 × 10^15 L. Therefore, the answer is B) 1.71 × 10^15 L.

Question 11

Write a balanced half equation for the following couple: NO₃^- NO₂^- (basic)

Accepted Answer

In a basic solution, water and hydroxide ions are used to balance the equation. The correct balanced half-equation is NO₃⁻ + H₂O + 2e⁻ → NO₂⁻ + 2OH⁻.

Question 12

What volume of 17 M nitric acid is required to dissolve 15 g of copper by a reaction for which the products are aqueous copper(II) nitrate, nitric oxide gas, and water? Assume 100% reaction.

Accepted Answer

The answer of What volume of 17 M nitric acid...

Question 13

Write a balanced half equation for the following couple: O₂ | OH- (basic)

Accepted Answer

In a basic solution, the reduction of O2 to OH- involves adding water and electrons to balance the equation: O2 + 2 H2O + 4 e- → 4 OH-.

Question 14

The compound of which P₄O₆ is the anhydride is ________.

Accepted Answer

The anhydride has the formula P₄O₆ which can be written as (HPO3)2. The compound that would form this anhydride would have one less oxygen atom than (HPO3)2, which is H2PO3, also known as phosphorous acid. Therefore, the only choice that fits this description is C, which is H₃PO₃.

Question 15

The pollution process in which oxygen depletion of natural waters by increased algae growth occurs because of contaminants such as excess phosphates is referred to as ________.

Accepted Answer

The pollution process described in the question is called eutrophication. This occurs when excess nutrients, such as phosphates, enter natural bodies of water and stimulate the overgrowth of algae. The algae then consumes the oxygen in the water as it decomposes, leading to oxygen depletion (anoxia) and potentially harming aquatic life. Biodegradation is the process by which organic matter is broken down by microorganisms, and phosphorylation is a chemical process involving the addition of phosphate groups to a molecule. Saponification refers to the reaction between a fat or oil and a base, resulting in the formation of soap.

Question 16

Which element is used as antiseptic and in medication for thyroid gland?

Accepted Answer

Iodine (I₂) is used as an antiseptic and also in medication for the thyroid gland as it is required for the synthesis of thyroid hormones.

Question 17

What is the pH of a solution labeled "0.30 M Hydroxylamine"? [Kb is 9.1 × 10^-9]

Accepted Answer

Hydroxylamine is a weak base. Using the Kb value, calculate the concentration of OH- ions, then find pOH and convert to pH. The pH is approximately 9.72.

Question 18

In certain automotive catalytic converters, one step involves the catalyzed reduction by carbon monoxide of nitric oxide (nitrogen monoxide) to nitrogen gas, with the carbon monoxide being converted to carbon dioxide. When the equation for this process is balanced, the sum of the coefficients is ________.

Accepted Answer

The balanced equation for the catalyzed reduction of nitric oxide by carbon monoxide is as follows:
2NO + 2CO → N2 + 2CO2
The sum of the coefficients is 2 + 2 + 1 + 2 = 7. Therefore, the best choice is C.

Question 19

What is the main commercial source of nitrogen?

Accepted Answer

The main commercial source of nitrogen is fractional distillation of liquid air, which separates nitrogen from other gases present in the air.

Question 20

In the compound dinitrogen monoxide, sometimes used as a dental anesthetic, the oxidation state of nitrogen is ________.

Accepted Answer

In dinitrogen monoxide (N2O), the total oxidation state of the compound must equal zero. Oxygen typically has an oxidation state of -2. With one oxygen atom, this gives -2 overall from oxygen. To balance this, the two nitrogen atoms together must contribute +2 to the overall charge, making each nitrogen atom have an oxidation state of +1.

Quiz 22: Main Group Elements II: Groups 18, 17, 16, 15, and Hydrogen

How much H₂ (in liters) is produced at 65°C and 670. torr by the reaction of 75.7 g of zinc? Zn(s) + 2 H+(aq) → Zn₂+(aq) + H₂(g)

Give the molecular shape of NO₃^-.

Write a balanced half equation for the following couple: NO₃^- | NH₄⁺(acidic)

Pyrosulfuric is also called disulfuric H₂S2O₇. Pyrosulfuric acid may be synthesized by dissolving SO₃ in ________.

How much H₂ (in liters) is produced at 45 °C and 770. torr by the reaction of 45.7 g of zinc? Zn(s) + 2 H+(aq) → Zn₂+(aq) + H₂(g)

Give the molecular shape of SO₄^2-.

Give the molecular shape of SO₂.

Write a balanced half equation for the following couple: SO₄^2- | S (acidic)

How much hydrogen (in liters at STP) is required to change 857 kg of diisobutylene to isooctane? Molar mass of diisobutylene is 112.2 grams. CH₃C(CH₃) ₂CH=C(CH₃) ₂ + H₂ → CH₃C(CH₃) ₂CH₂CH(CH₃) ₂

Write a balanced half equation for the following couple: NO₃^- NO₂^- (basic)

What volume of 17 M nitric acid is required to dissolve 15 g of copper by a reaction for which the products are aqueous copper(II) nitrate, nitric oxide gas, and water? Assume 100% reaction.

Write a balanced half equation for the following couple: O₂ | OH- (basic)

The compound of which P₄O₆ is the anhydride is ________.

The pollution process in which oxygen depletion of natural waters by increased algae growth occurs because of contaminants such as excess phosphates is referred to as ________.

Which element is used as antiseptic and in medication for thyroid gland?

What is the pH of a solution labeled "0.30 M Hydroxylamine"? [Kb is 9.1 × 10^-9]

What is the main commercial source of nitrogen?

In the compound dinitrogen monoxide, sometimes used as a dental anesthetic, the oxidation state of nitrogen is ________.

Quiz 22: Main Group Elements II: Groups 18, 17, 16, 15, and Hydrogen

How much H2 (in liters) is produced at 65°C and 670. torr by the reaction of 75.7 g of zinc? Zn(s) + 2 H+(aq) → Zn2+(aq) + H2(g)

Give the molecular shape of NO3-.

Write a balanced half equation for the following couple: NO3- | NH4+(acidic)

Pyrosulfuric is also called disulfuric H2S2O7. Pyrosulfuric acid may be synthesized by dissolving SO3 in ________.

How much H2 (in liters) is produced at 45 °C and 770. torr by the reaction of 45.7 g of zinc? Zn(s) + 2 H+(aq) → Zn2+(aq) + H2(g)

Give the molecular shape of SO42-.

Give the molecular shape of SO2.

Write a balanced half equation for the following couple: SO42- | S (acidic)

How much hydrogen (in liters at STP) is required to change 857 kg of diisobutylene to isooctane? Molar mass of diisobutylene is 112.2 grams. CH3C(CH3) 2CH=C(CH3) 2 + H2 → CH3C(CH3) 2CH2CH(CH3) 2

Write a balanced half equation for the following couple: NO3- NO2- (basic)

What volume of 17 M nitric acid is required to dissolve 15 g of copper by a reaction for which the products are aqueous copper(II) nitrate, nitric oxide gas, and water? Assume 100% reaction.

Write a balanced half equation for the following couple: O2 | OH- (basic)

The compound of which P4O6 is the anhydride is ________.

The pollution process in which oxygen depletion of natural waters by increased algae growth occurs because of contaminants such as excess phosphates is referred to as ________.

Which element is used as antiseptic and in medication for thyroid gland?

What is the pH of a solution labeled "0.30 M Hydroxylamine"? [Kb is 9.1 × 10-9]

What is the main commercial source of nitrogen?

In the compound dinitrogen monoxide, sometimes used as a dental anesthetic, the oxidation state of nitrogen is ________.

How much H₂ (in liters) is produced at 65°C and 670. torr by the reaction of 75.7 g of zinc? Zn(s) + 2 H+(aq) → Zn₂+(aq) + H₂(g)

Give the molecular shape of NO₃^-.

Write a balanced half equation for the following couple: NO₃^- | NH₄⁺(acidic)

Pyrosulfuric is also called disulfuric H₂S2O₇. Pyrosulfuric acid may be synthesized by dissolving SO₃ in ________.

How much H₂ (in liters) is produced at 45 °C and 770. torr by the reaction of 45.7 g of zinc? Zn(s) + 2 H+(aq) → Zn₂+(aq) + H₂(g)

Give the molecular shape of SO₄^2-.

Give the molecular shape of SO₂.

Write a balanced half equation for the following couple: SO₄^2- | S (acidic)

How much hydrogen (in liters at STP) is required to change 857 kg of diisobutylene to isooctane? Molar mass of diisobutylene is 112.2 grams. CH₃C(CH₃) ₂CH=C(CH₃) ₂ + H₂ → CH₃C(CH₃) ₂CH₂CH(CH₃) ₂

Write a balanced half equation for the following couple: NO₃^- NO₂^- (basic)

Write a balanced half equation for the following couple: O₂ | OH- (basic)

The compound of which P₄O₆ is the anhydride is ________.

What is the pH of a solution labeled "0.30 M Hydroxylamine"? [Kb is 9.1 × 10^-9]