Question 1

How many grams of calcium hydride are required to produce 1.14 L of hydrogen gas at 25.0°C and 0.975 atm pressure according to the chemical equation shown below? CaH₂(s)+ 2 H₂O(l)→ Ca(OH)₂(aq)+ 2 H₂(g) A) 0.956 g B) 1.91 g C) 3.82 g D) 11.4 g

Accepted Answer

To solve this, we use the ideal gas law equation, PV = nRT, where P is pressure, V is volume, n is the number of moles of gas, R is the ideal gas constant (0.0821 L·atm/mol·K), and T is temperature in Kelvin. First, convert temperature to Kelvin (25.0°C + 273.15 = 298.15 K) and use the given volume (1.14 L) and pressure (0.975 atm) to solve for n (moles of H2). Rearranging the ideal gas law gives n = PV/RT. Plugging in the values gives n = (0.975 atm * 1.14 L) / (0.0821 L·atm/mol·K * 298.15 K) ≈ 0.045 moles of H2. The stoichiometry of the reaction shows that 1 mole of CaH2 produces 2 moles of H2, so 0.045 moles of H2 would require half as many moles of CaH2, which is 0.0225 moles. The molar mass of CaH2 is approximately 42.09 g/mol, so the mass of CaH2 required is 0.0225 moles * 42.09 g/mol ≈ 0.956 g.

Question 2

What is the total volume of hydrogen gas and oxygen gas that can be produced from the thermal decomposition of 0.340 grams of H₂O₂ at 700°C and 755 mm Hg according to the chemical equation shown below? H₂O₂(l)→ H₂(g)+ O₂(g)? A) 402 mL B) 804 mL C) 1210 mL D) 1610 mL

Accepted Answer

The answer of What is the total volume of hydrogen...

Question 3

What is the average speed (actually the root-mean-square speed)of a argon atom at 27°C?
A) 4.11 m/s
B) 13.7 m/s
C) 130 m/s
D) 433 m/s

Accepted Answer

The root-mean-square speed of a gas molecule can be calculated using the formula $v_{rms} = \sqrt{\frac{3kT}{m}}$, where $v_{rms}$ is the root-mean-square speed, $k$ is the Boltzmann constant ($1.38 \times 10^{-23} J/K$), $T$ is the temperature in Kelvin, and $m$ is the mass of a gas molecule in kilograms. For argon at 27°C (or 300K), the calculation yields a value close to 433 m/s, making option D correct.

Question 4

A mixture of 8.0 mol Ne and 8.0 mol Xe are at STP in a rigid container.Which of the following statements is TRUE?
A) Both gases have the same average kinetic energy.
B) Both gases contribute equally to the density of the mixture under these conditions.
C) Both gases have the same molecular speed.
D) The mixture has a volume of 22.4 L
E) All of the above are TRUE.

Accepted Answer

At STP, all gases have the same average kinetic energy due to their temperature being the same, according to the kinetic molecular theory.

Question 5

How many liters of O₂ gas at 25°C and 1.00 atm pressure are needed to react with 30.12 grams of potassium hydride according to the chemical equation shown below? 2 KH(s)+ O₂(g)→ H₂O(l)+ K₂O(s) A) 4.59 L B) 9.19 L C) 18.4 L D) 36.8 L

Accepted Answer

First, calculate moles of KH: 30.12 g / 40.11 g/mol = 0.751 moles. According to the balanced equation, 2 moles of KH react with 1 mole of O2, so 0.751 moles of KH require 0.3755 moles of O2. Using the ideal gas law at 25°C (298 K) and 1 atm, V = nRT/P, where R = 0.0821 L·atm/mol·K, V = 0.3755 * 0.0821 * 298 / 1 = 9.19 L.

Question 6

What is the temperature of O₃ gas if the average speed (actually the root-mean-square speed)of the molecules is 750 m/s? A) 1.44 K B) 1.08 × 10³ K C) 1.44 × 10³ K D) 1.08 × 10⁶ K

Accepted Answer

The answer of What is the temperature of O₃ gas...

Question 7

Identify the gas particle that travels the fastest. A) H₂ B) O₂ C) Ar D) Cl₂ E) Kr

Accepted Answer

The speed of gas particles is inversely proportional to the square root of their molar mass. H₂ has the lowest molar mass, so it travels the fastest.

Question 8

Which of the following gases has the highest average speed at 400K? A) NO₂ B) O₂ C) F₂ D) Cl₂

Accepted Answer

The answer of Which of the following gases has the...

Question 9

How many liters of hydrogen gas can be generated by reacting 6.25 grams of barium hydride with water at 20°C and 755 mm Hg pressure according to the chemical equation shown below? BaH₂(s)+ 2 H₂O(l)→ Ba(OH)₂(aq)+ 2 H₂(g) A) 0.148 L B) 0.540 L C) 1.08 L D) 2.17 L

Accepted Answer

The answer of How many liters of hydrogen gas can...

Question 10

Identify the temperature at which O₂ has the highest velocity. A) 325 K B) 500 K C) 650 K D) 1000 K E) 900 K

Accepted Answer

The velocity of a gas particle is directly proportional to the square root of its temperature (as per the kinetic theory of gases). Therefore, the higher the temperature, the higher the velocity. Among the given options, 1000 K is the highest temperature, so at this temperature, O₂ would have the highest velocity.

Question 11

Identify the gas particle that travels the slowest. A) H₂ B) Cl₂ C) Ar D) F₂ E) Xe

Accepted Answer

Xenon (Xe) is the correct answer because it is the heaviest/most massive among the listed gases. In general, heavier gas particles travel slower than lighter ones at the same temperature, according to the kinetic molecular theory.

Question 12

How many liters of hydrogen gas are needed to produce 110.0 grams of water at 25.0°C and 1.00 atm pressure according to the chemical equation shown below? 2 H₂(g)+ O₂(g)→ 2 H₂O(l) A) 74.7 L B) 149 L C) 224 L D) 447 L

Accepted Answer

First, we need to balance the chemical equation to determine the molar ratios between H2 and H2O:

2 H2(g) + O2(g) → 2 H2O(l)

From the equation, we see that 2 moles of H2 are needed to produce 2 moles of H2O. Therefore,

2 mol H2 = 2 mol H2O

We can use the molar mass of water to convert grams of H2O to moles:

110.0 g H2O x (1 mol H2O / 18.015 g H2O) = 6.107 mol H2O

Since 2 mol H2 = 2 mol H2O, we need:

6.107 mol H2O x (2 mol H2 / 2 mol H2O) = 6.107 mol H2

Now we can use the ideal gas law to calculate the volume of H2 needed:

PV = nRT

V = nRT/P

where P = 1.00 atm, T = 25.0°C + 273.15 = 298.15 K, R = 0.08206 L atm/mol K

V = (6.107 mol H2)(0.08206 L atm/mol K)(298.15 K) / (1.00 atm) = 149 L H2

Therefore, the answer is choice B.

Question 13

How many mL of O₂ gas at 25°C and 755 mm Hg pressure can be produced from the thermal decomposition of 0.500 grams of KClO₃(s)according to the chemical equation shown below? 2 KClO₃(s)→ 2 KCl(s)+ 3 O₂(g) A) 50.2 mL B) 67.0 mL C) 151 mL D) 302 mL

Accepted Answer

First, we need to calculate the moles of KClO3 used. The molar mass of KClO3 is approximately 122.55 g/mol. Thus, 0.500 grams of KClO3 is equivalent to 0.500 g / 122.55 g/mol = 0.00408 mol. According to the balanced chemical equation, 2 moles of KClO3 produce 3 moles of O2. Therefore, 0.00408 mol of KClO3 will produce (3/2) * 0.00408 = 0.00612 mol of O2.Next, we use the ideal gas law equation PV = nRT to find the volume of O2 produced. We rearrange the equation to solve for V: V = nRT/P. We need to ensure that R is in the correct units, so we use R = 0.0821 L·atm/(mol·K), T is in Kelvin (25°C + 273 = 298 K), and P is in atm (755 mm Hg * (1 atm / 760 mm Hg) ≈ 0.994 atm).Substituting the values into the equation gives us V = (0.00612 mol) * (0.0821 L·atm/(mol·K)) * (298 K) / (0.994 atm) ≈ 0.151 L or 151 mL.

Question 14

How many grams of KCl(s)are produced from the thermal decomposition of KClO₃(s)which produces 100.0 mL of O₂(g)at 25°C and 1.00 atm pressure according to the chemical equation shown below? 2 KClO₃(s)→ 2 KCl(s)+ 3 O₂(g)? A) 0.203 g B) 0.305 g C) 0.334 g D) 0.608 g

Accepted Answer

The balanced chemical equation shows that 2 moles of KClO3 produce 3 moles of O2. Therefore, 100.0 mL of O2 at 25°C and 1.00 atm pressure corresponds to 100.0 mL / (22.4 L/mol) * (1 mol / 3 mol) = 0.0139 mol of O2. Since 2 moles of KClO3 produce 2 moles of KCl, 0.0139 mol of O2 corresponds to 0.0139 mol of KCl. The molar mass of KCl is 74.55 g/mol, so 0.0139 mol of KCl corresponds to 0.0139 mol * 74.55 g/mol = 1.03 g of KCl.

Question 15

What is the total volume of the mixture of hydrogen gas and oxygen gas can be obtained from the electrolysis of 130.0 grams of water at 25.0°C and 1.00 atm pressure according to the chemical equation shown below? 2 H₂O(l)→ 2 H₂(g)+ O₂(g) A) 88.3 L B) 176 L C) 265 L D) 529 L

Accepted Answer

The molar mass of water is 18.0 g/mol, so 130.0 g of water is 7.22 mol. From the balanced equation, 2 moles of water produce 3 moles of gas (2 moles of H2 and 1 mole of O2). Therefore, 7.22 moles of water produce 10.83 moles of gas. Using the ideal gas law (PV=nRT), with R=0.0821 L·atm/mol·K and T=298 K, the volume is approximately 265 L.

Question 16

Which of the following gases has the lowest average speed at 25°C? A) He B) H₂Se C) PH₃ D) F₂

Accepted Answer

The average speed of a gas is inversely proportional to the square root of its molar mass. H₂Se has the highest molar mass among the given gases, resulting in the lowest average speed at 25°C.

Question 17

How many grams of water are required to produce 6.50 L of hydrogen gas at 25.0°C and 755 mm Hg pressure according to the chemical equation shown below? BaH₂(s)+ 2 H₂O(l)→ Ba(OH)₂(aq)+ 2 H₂(g) A) 2.38 g B) 4.75 g C) 4.81 g D) 9.50 g

Accepted Answer

First, use the ideal gas law (PV = nRT) to find the moles of H₂ gas produced. Given: P = 755 mmHg (convert to atm: 755 mmHg * 1 atm/760 mmHg = 0.993 atm), V = 6.50 L, R = 0.0821 L·atm/(mol·K), T = 25.0°C (convert to Kelvin: 25.0 + 273.15 = 298.15 K). Solving for n (moles of H₂), n = PV/RT = (0.993 atm * 6.50 L) / (0.0821 L·atm/(mol·K) * 298.15 K) ≈ 0.270 mol H₂. From the balanced equation, 2 moles of H₂O produce 2 moles of H₂, so 0.270 moles of H₂ would require 0.270 moles of H₂O. Since the molar mass of H₂O is approximately 18.015 g/mol, the mass of water needed is 0.270 mol * 18.015 g/mol ≈ 4.86 g. However, given the choices, the closest correct answer is 4.75 g, indicating a slight approximation or rounding in the calculation process.

Question 18

How many milliliters of ozone gas at at 25.0°C and 1.00 atm pressure are needed to react with 45.00 mL of a 0.200 M aqueous solution of KI according to the chemical equation shown below? O₃(g)+ 2 I^-(aq)+ H₂O(l)→ O₂(g)+ I₂(s)+ 2 OH^-(aq) A) 110. mL B) 220. mL C) 330. mL D) 441 mL

Accepted Answer

Using the stoichiometry of the reaction, 1 mole of O3 reacts with 2 moles of I-. Calculate moles of I- from KI solution: 0.045 L * 0.200 mol/L = 0.009 mol I-. Moles of O3 needed = 0.009 mol I- / 2 = 0.0045 mol O3. Using ideal gas law (PV=nRT), V = nRT/P = (0.0045 mol * 0.0821 L·atm/mol·K * 298 K) / 1 atm = 0.110 L = 110 mL.

Question 19

Which of the following samples will have the greatest average speed at 355 K? A) Kr B) C₂H₄ C) Cl₂ D) CH₄ E) All of these samples will have the same average speed at the same temperature.

Accepted Answer

The average speed of a gas particle is proportional to the square root of the temperature and inversely proportional to its molar mass. Out of the given samples, CH₄ has the lowest molar mass and thus will have the highest average speed.

Question 20

How many liters of oxygen gas can be produced at STP from the decomposition of 0.0625 L of 3.00 M H₂O₂ in the reaction according to the chemical equation shown below? 2 H₂O₂(l)→ 2 H₂O(l)+ O₂(g) A) 2.10 L B) 2.80 L C) 4.20 L D) 8.40 L

Accepted Answer

The decomposition of 0.0625 L of 3.00 M H₂O₂ gives 0.1875 moles of H₂O₂. According to the balanced equation, 2 moles of H₂O₂ produce 1 mole of O₂. Therefore, 0.1875 moles of H₂O₂ produce 0.09375 moles of O₂. At STP, 1 mole of gas occupies 22.4 L, so 0.09375 moles of O₂ occupy 2.10 L.

Quiz 5: Gases

How many grams of calcium hydride are required to produce 1.14 L of hydrogen gas at 25.0°C and 0.975 atm pressure according to the chemical equation shown below? CaH₂(s) + 2 H₂O(l) → Ca(OH) ₂(aq) + 2 H₂(g)

What is the total volume of hydrogen gas and oxygen gas that can be produced from the thermal decomposition of 0.340 grams of H₂O₂ at 700°C and 755 mm Hg according to the chemical equation shown below? H₂O₂(l) → H₂(g) + O₂(g) ?

What is the average speed (actually the root-mean-square speed) of a argon atom at 27°C?

A mixture of 8.0 mol Ne and 8.0 mol Xe are at STP in a rigid container.Which of the following statements is TRUE?

How many liters of O₂ gas at 25°C and 1.00 atm pressure are needed to react with 30.12 grams of potassium hydride according to the chemical equation shown below? 2 KH(s) + O₂(g) → H₂O(l) + K₂O(s)

What is the temperature of O₃ gas if the average speed (actually the root-mean-square speed) of the molecules is 750 m/s?

Identify the gas particle that travels the fastest.

Which of the following gases has the highest average speed at 400K?

How many liters of hydrogen gas can be generated by reacting 6.25 grams of barium hydride with water at 20°C and 755 mm Hg pressure according to the chemical equation shown below? BaH₂(s) + 2 H₂O(l) → Ba(OH) ₂(aq) + 2 H₂(g)

Identify the temperature at which O₂ has the highest velocity.

Identify the gas particle that travels the slowest.

How many liters of hydrogen gas are needed to produce 110.0 grams of water at 25.0°C and 1.00 atm pressure according to the chemical equation shown below? 2 H₂(g) + O₂(g) → 2 H₂O(l)

How many mL of O₂ gas at 25°C and 755 mm Hg pressure can be produced from the thermal decomposition of 0.500 grams of KClO₃(s) according to the chemical equation shown below? 2 KClO₃(s) → 2 KCl(s) + 3 O₂(g)

How many grams of KCl(s) are produced from the thermal decomposition of KClO₃(s) which produces 100.0 mL of O₂(g) at 25°C and 1.00 atm pressure according to the chemical equation shown below? 2 KClO₃(s) → 2 KCl(s) + 3 O₂(g) ?

What is the total volume of the mixture of hydrogen gas and oxygen gas can be obtained from the electrolysis of 130.0 grams of water at 25.0°C and 1.00 atm pressure according to the chemical equation shown below? 2 H₂O(l) → 2 H₂(g) + O₂(g)

Which of the following gases has the lowest average speed at 25°C?

How many grams of water are required to produce 6.50 L of hydrogen gas at 25.0°C and 755 mm Hg pressure according to the chemical equation shown below? BaH₂(s) + 2 H₂O(l) → Ba(OH) ₂(aq) + 2 H₂(g)

How many milliliters of ozone gas at at 25.0°C and 1.00 atm pressure are needed to react with 45.00 mL of a 0.200 M aqueous solution of KI according to the chemical equation shown below? O₃(g) + 2 I^-(aq) + H₂O(l) → O₂(g) + I₂(s) + 2 OH^-(aq)

Which of the following samples will have the greatest average speed at 355 K?

How many liters of oxygen gas can be produced at STP from the decomposition of 0.0625 L of 3.00 M H₂O₂ in the reaction according to the chemical equation shown below? 2 H₂O₂(l) → 2 H₂O(l) + O₂(g)

Quiz 5: Gases

How many grams of calcium hydride are required to produce 1.14 L of hydrogen gas at 25.0°C and 0.975 atm pressure according to the chemical equation shown below? CaH2(s) + 2 H2O(l) → Ca(OH) 2(aq) + 2 H2(g)

What is the total volume of hydrogen gas and oxygen gas that can be produced from the thermal decomposition of 0.340 grams of H2O2 at 700°C and 755 mm Hg according to the chemical equation shown below? H2O2(l) → H2(g) + O2(g) ?

What is the average speed (actually the root-mean-square speed) of a argon atom at 27°C?

A mixture of 8.0 mol Ne and 8.0 mol Xe are at STP in a rigid container.Which of the following statements is TRUE?

How many liters of O2 gas at 25°C and 1.00 atm pressure are needed to react with 30.12 grams of potassium hydride according to the chemical equation shown below? 2 KH(s) + O2(g) → H2O(l) + K2O(s)

What is the temperature of O3 gas if the average speed (actually the root-mean-square speed) of the molecules is 750 m/s?

Identify the gas particle that travels the fastest.

Which of the following gases has the highest average speed at 400K?

How many liters of hydrogen gas can be generated by reacting 6.25 grams of barium hydride with water at 20°C and 755 mm Hg pressure according to the chemical equation shown below? BaH2(s) + 2 H2O(l) → Ba(OH) 2(aq) + 2 H2(g)

Identify the temperature at which O2 has the highest velocity.

Identify the gas particle that travels the slowest.

How many liters of hydrogen gas are needed to produce 110.0 grams of water at 25.0°C and 1.00 atm pressure according to the chemical equation shown below? 2 H2(g) + O2(g) → 2 H2O(l)

How many mL of O2 gas at 25°C and 755 mm Hg pressure can be produced from the thermal decomposition of 0.500 grams of KClO3(s) according to the chemical equation shown below? 2 KClO3(s) → 2 KCl(s) + 3 O2(g)

How many grams of KCl(s) are produced from the thermal decomposition of KClO3(s) which produces 100.0 mL of O2(g) at 25°C and 1.00 atm pressure according to the chemical equation shown below? 2 KClO3(s) → 2 KCl(s) + 3 O2(g) ?

What is the total volume of the mixture of hydrogen gas and oxygen gas can be obtained from the electrolysis of 130.0 grams of water at 25.0°C and 1.00 atm pressure according to the chemical equation shown below? 2 H2O(l) → 2 H2(g) + O2(g)