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

7. Gases

The Ideal Gas Law: Molar Mass

General Chemistry

7. Gases

The Ideal Gas Law: Molar Mass

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Multiple Choice

A 22.0-g sample of an unknown gas occupies a volume of 11.2 L at STP. What could be the identity of the gas?

Neon (Ne)

Nitrogen (N2)

Carbon dioxide (CO2)

Oxygen (O2)

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Verified step by step guidance

Start by recalling the conditions at STP (Standard Temperature and Pressure), which are 0°C (273.15 K) and 1 atm pressure. At STP, 1 mole of an ideal gas occupies 22.4 L.

Use the ideal gas law to determine the molar mass of the unknown gas. The formula is: \( \text{Molar Mass} = \frac{\text{Mass}}{\text{Moles}} \). First, calculate the number of moles using the volume at STP: \( \text{Moles} = \frac{\text{Volume}}{22.4 \text{ L/mol}} \).

Substitute the given values into the formula: \( \text{Moles} = \frac{11.2 \text{ L}}{22.4 \text{ L/mol}} \). This will give you the number of moles of the gas.

Next, calculate the molar mass using the mass of the gas sample and the moles calculated: \( \text{Molar Mass} = \frac{22.0 \text{ g}}{\text{Moles}} \).

Compare the calculated molar mass to the known molar masses of the given gases: Neon (Ne), Nitrogen (N2), Carbon dioxide (CO2), and Oxygen (O2). The gas with the closest molar mass to your calculated value is likely the identity of the unknown gas.