Question 1
Paper 2Hard12 marksA laboratory is checking whether the ideal-gas model gives reliable volume estimates for gases in a transfer line. Samples of carbon dioxide and methane are measured at The table gives their measured molar volumes and the ideal-gas molar volume at each pressure.
| Pressure / bar | Ideal-gas molar volume / dm³ mol⁻¹ | Measured CO₂ molar volume / dm³ mol⁻¹ | Measured CH₄ molar volume / dm³ mol⁻¹ |
|---|---|---|---|
| 1.00 | 23.3 | 23.1 | 23.2 |
| 5.00 | 4.66 | 4.54 | 4.63 |
| 10.0 | 2.33 | 2.14 | 2.29 |
| 20.0 | 1.16 | 0.94 | 1.11 |
Use Figure 1 to determine the molecular formula of each gas.
For an ideal-gas sample of at and calculate the molar volume. Give your answer in to three significant figures. Use the ideal gas equation in the data booklet.
At compare the measured molar volume of each gas with the ideal-gas value.
Explain why real gases are more likely to deviate from the ideal-gas model at low temperature and high pressure.
A technician argues that the ideal-gas model is equally reliable for carbon dioxide and methane at and because the ideal molar volume is the same for both gases. Evaluate this argument using the table and Figure 1.