10-minute Quiz : Chapter 38

0.580 g of a hydrocarbon contains 0.480 g of carbon and 0.100 g of hydrogen. At room temperature and pressure, 24.0 cm³ of this gaseous hydrocarbon has a mass of 0.0870 g. What is the molecular formula for this hydrocarbon?

(Relative atomic masses: H = 1.0, C = 12.0; molar volume of gas at room temperature and pressure = 24 dm³ mol⁻¹)

• A. C₂H₅
• B. C₃H₅
• C. C₄H₁₀
• D. C₆H₁₅

Consider the reaction between nitrogen and hydrogen to form ammonia.

N₂(g) + 3H₂(g) → 2NH₃(g)

The rate of formation of NH₃(g), measured at room temperature and pressure, is 0.300 mol min⁻¹. What is the rate of consumption of H₂(g) under the same conditions?

(Molar volume of gas at room temperature and pressure = 24 dm³ mol⁻¹)

• A. 3.6 dm³ min⁻¹

• B. 4.8 dm³ min⁻¹

• C. 10.8 dm³ min⁻¹

• D. 21.6 dm³ min⁻¹

What is the number of molecules in 8.0 g of oxygen?

(Relative atomic mass: O = 16.0; Avogadro constant = 6.02 × 10²³ mol⁻¹)

• A. 1.5 × 10²³
• B. 3.2 × 10²³
• C. 4.3 × 10²³
• D. 6.0 × 10²³

What is the volume of oxygen, measured at room temperature and pressure, required for the complete combustion of 1.0 dm³ of butane?

2C₄H₁₀(g) + 13O₂(g) → 8CO₂(g) + 10H₂O(l)

• A. 1.0 dm³
• B. 4.0 dm³
• C. 6.5 dm³
• D. 13 dm³

Which of the following gases has the largest volume, measured at room temperature and pressure?

(Relative atomic masses: H = 1.0, C = 12.0, N = 14.0, Cl = 35.5; molar volume of gas at room temperature and pressure = 24 dm³ mol⁻¹)

• A. 0.10 g of hydrogen
• B. 0.17 g of ammonia
• C. 0.32 g of methane
• D. 0.35 g of chlorine

0.30 mol of zinc is added to 750 cm³ of 1.0 M hydrochloric acid. What is the volume of hydrogen formed, measured at room temperature and pressure?

Zn(s) + 2HCl(aq) → ZnCl₂(aq) + H₂(g)

(Molar volume of gas at room temperature and pressure = 24 dm³ mol⁻¹)

• A. 300.0 dm³
• B. 75.6 dm³
• C. 22.7 dm³
• D. 7.2 dm³

Direction: Questions 7 to 9 refer to the experiment.

In an experiment, 100 cm³ of hydrogen was mixed with 25 cm³ of oxygen and then ignited by an electric heater, as shown in the diagram. Given that the reaction occurred at 150°C, what was the gas volume at the end of the reaction?

(Assume that all gas volumes were measured at the same temperature and pressure.)

• A. 50 cm³
• B. 100 cm³
• C. 125 cm³
• D. 150 cm³

Direction: Questions 7 to 9 refer to the experiment.

The gaseous mixture, after the reaction, was then allowed to cool to room temperature under atmospheric pressure. What would be the gas volume after cooling?

(Assume that all gas volumes were measured at the same temperature and pressure.)

• A. 50 cm³
• B. 100 cm³
• C. 125 cm³
• D. 150 cm³

Direction: Questions 7 to 9 refer to the experiment.

What was the mass of hydrogen reacted if the vessel contained 4.8 g of oxygen?

(Relative atomic masses: H = 1.0, O = 16.0)

• A. 4.8 g
• B. 3.0 g
• C. 0.6 g
• D. 0.3 g

Which of the following statements about 1 dm³ of neon and 1 dm³ of fluorine, measured at the same temperature and pressure, is/are correct?

(1) Both of them contain the same number of atoms.

(2) Both of them contain the same number of molecules.

(3) They have the same mass.

• A. (1) only
• B. (2) only
• C. (1) and (3) only
• D. (2) and (3) only