Table of contents

1. Intro to General Chemistry3h 48m
2. Atoms & Elements4h 16m
3. Chemical Reactions4h 10m
4. BONUS: Lab Techniques and Procedures1h 38m
5. BONUS: Mathematical Operations and Functions48m
6. Chemical Quantities & Aqueous Reactions3h 53m
7. Gases3h 49m
8. Thermochemistry2h 37m
9. Quantum Mechanics2h 58m
10. Periodic Properties of the Elements3h 9m
11. Bonding & Molecular Structure3h 29m
12. Molecular Shapes & Valence Bond Theory1h 57m
13. Liquids, Solids & Intermolecular Forces2h 23m
14. Solutions3h 1m
15. Chemical Kinetics2h 53m
16. Chemical Equilibrium2h 29m
17. Acid and Base Equilibrium5h 1m
18. Aqueous Equilibrium4h 47m
19. Chemical Thermodynamics1h 50m
20. Electrochemistry2h 42m
21. Nuclear Chemistry2h 36m
22. Organic Chemistry5h 7m
23. Chemistry of the Nonmetals2h 39m
24. Transition Metals and Coordination Compounds3h 16m

3. Chemical Reactions

Stoichiometry

General Chemistry

3. Chemical Reactions

Stoichiometry

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Multiple Choice

How many liters of H2 gas, collected over water at an atmospheric pressure of 752 mm Hg and a temperature of 21.0°C, can be produced from 5.566 g of Zn reacting with excess HCl? The partial pressure of water vapor is 18.65 mm Hg.

2.72 L

3.00 L

2.24 L

2.48 L

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Verified step by step guidance

First, write the balanced chemical equation for the reaction between zinc (Zn) and hydrochloric acid (HCl): \( \text{Zn} + 2\text{HCl} \rightarrow \text{ZnCl}_2 + \text{H}_2 \). This shows that 1 mole of Zn produces 1 mole of H2 gas.

Calculate the number of moles of Zn using its molar mass. The molar mass of Zn is approximately 65.38 g/mol. Use the formula: \( \text{moles of Zn} = \frac{\text{mass of Zn}}{\text{molar mass of Zn}} \).

Determine the moles of H2 gas produced. Since the reaction is a 1:1 mole ratio between Zn and H2, the moles of H2 gas will be equal to the moles of Zn calculated in the previous step.

Use the ideal gas law to find the volume of H2 gas. The ideal gas law is \( PV = nRT \), where \( P \) is the pressure of the gas, \( V \) is the volume, \( n \) is the number of moles, \( R \) is the ideal gas constant (0.0821 L·atm/mol·K), and \( T \) is the temperature in Kelvin. First, convert the temperature from Celsius to Kelvin by adding 273.15.

Adjust the pressure to account for the water vapor. The total pressure is given as 752 mm Hg, and the partial pressure of water vapor is 18.65 mm Hg. Subtract the water vapor pressure from the total pressure to find the pressure of the H2 gas alone. Convert this pressure from mm Hg to atm by dividing by 760 mm Hg/atm. Use this pressure in the ideal gas law to solve for the volume \( V \) of H2 gas.