The method and the results are on the ideal gas equation lab. Do the analysis yourself first, then check the answers below.
Quick answer: The amount of substance, in mol, links mass, particle number, solution volume and gas volume. These answers go with the Chemistry 11-12 lab on ideal gas equation: the graph, the calculations, the uncertainties and the conclusion explained, for all 8 analysis questions.
Here are the ideal gas equation lab answers for chemistry grades 11-12: graph, calculations, uncertainties and conclusion. First do the lab yourself, then compare, and go back to the lesson if needed.
The model answers use R = 8.31 J K⁻¹ mol⁻¹ and the partial pressure of butane after subtracting the water vapour pressure. Rounding differences in the last figure are acceptable.
Level: Chemistry grades 11-12 (A Level · IB · Class 11-12) · Curriculum: A Level 3.1.2
Two readings, each ±0.01 g, give ±0.02 g on the loss. Percentage uncertainty = 0.02 ÷ 0.24 × 100 = 8.3 %.
Question 7 Systematic error
Some butane dissolves, so the measured volume of gas is too small. The amount n is too small, and M = m ÷ n is too large. The calculated molar mass is too high.
Question 8 Improvement
Collect a larger volume and mass (for example 250 cm³ with a bigger mass loss) so that the fixed ±0.02 g uncertainty becomes a smaller percentage, or use a balance reading to 0.001 g.
