中文（繁體）
中文（简体）
English
S4 Chemistry: Molar Volume and Gas Calculations (Paper 1: Basics)
S4 Chemistry: Molar Volume and Gas Calculations (Paper 1: Basics)
Ten questions built on the molar volume of 24 dm3/mol, practising conversions between moles, mass and gas volume, with answers and one line notes.
Direct answers Answers in order: 48 dm3, 6.0 dm3, 3.0 mol, 6.0 dm3, 2.4 dm3, 0.010 mol, equal volumes, 1.0 g and 12 dm3, 2.4 dm3, room conditions need 24 dm3.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 |
| Suggested time | 20 |
| Difficulty mix | Foundation 3 · Intermediate 3 · Challenge 3 · Error redo 1 |
| Chapter | Chapter: S4 Chemistry: Molar Volume and Gas Calculations |
| Level | S4 |
02 Questions (10 items)
- FoundationAt room temperature and pressure, what volume does 2.0 mol of oxygen occupy, taking the molar volume as 24 dm3/mol?
- FoundationWhat volume does 0.250 mol of carbon dioxide occupy at room temperature and pressure?
- FoundationA gas occupies 72 dm3 at room temperature and pressure. How many moles are present?
- IntermediateWhat volume does 8.0 g of oxygen occupy at room temperature and pressure, with O2 equal to 32?
- IntermediateWhat volume does 4.4 g of carbon dioxide occupy at room temperature and pressure, with CO2 equal to 44?
- IntermediateHow many moles are there in 240 cm3 of gas at room temperature and pressure?
- ChallengeAt the same temperature and pressure, how do the volumes of 1 mol of oxygen and 1 mol of hydrogen compare?
- ChallengeWhat are the mass and the volume of 0.50 mol of hydrogen, with H2 equal to 2?
- ChallengeWhat volume does 1.6 g of methane occupy at room temperature and pressure, with CH4 equal to 16?
- Error redoA student answers that 1 mol of any gas occupies 22.4 dm3 at room temperature and pressure. What is wrong?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | 48 dm3 | Volume equals moles times molar volume, so 2.0 times 24 gives 48 dm3. |
| 2 | 6.0 dm3 | 0.250 times 24 gives 6.0 dm3, and the identity of the gas does not matter. |
| 3 | 3.0 mol | Dividing 72 by 24 gives 3.0 mol. |
| 4 | 6.0 dm3 | First find the moles: 8.0 divided by 32 is 0.250 mol, then multiply by 24. |
| 5 | 2.4 dm3 | 4.4 divided by 44 is 0.10 mol, and multiplying by 24 gives 2.4 dm3. |
| 6 | 0.010 mol | Convert 240 cm3 to 0.240 dm3 first, then divide by 24. |
| 7 | They are equal, both 24 dm3 | The molar volume is the same at a given temperature and pressure, so equal moles give equal volume, which is Avogadro law. |
| 8 | Mass 1.0 g and volume 12 dm3 | The mass is 0.50 times 2, giving 1.0 g, and the volume is 0.50 times 24, giving 12 dm3. |
| 9 | 2.4 dm3 | 1.6 divided by 16 is 0.10 mol, and 0.10 times 24 gives 2.4 dm3. |
| 10 | Wrong. The molar volume at room temperature and pressure is 24 dm3, while 22.4 dm3 applies at s.t.p. of 0 degrees Celsius and 1 atm. | The two sets of conditions differ in temperature and pressure, so a question stating room conditions must use 24 dm3. |
04 What to do after marking
- After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
- Repeat the same item two days later; move to the next paper only when both attempts are correct.
- Parents only need the answer and note columns; there is no need to explain every item.
Write the moles first and the volume second; keeping the two steps apart prevents confusion.Tutor Registration →
Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.