A chemist investigates the pressure–mole relationship for methane gas (CH₄) in a sealed
CHEMISTRY · Multi-part · A Level · Chemistry · Amount of substance · Amount of substance
Problem
A chemist investigates the pressure–mole relationship for methane gas (CH₄) in a sealed, rigid vessel at 298 K. After each addition of CH₄, the pressure is recorded:
Moles CH₄ (mol): 0.10 0.20 0.30 0.40
Pressure (atm): 0.245 0.490 0.735 0.980
(a) Using proportional reasoning, discuss whether the data are consistent with ideal-gas behavior. Support your answer with evidence from the table.
(b) Determine the numerical value of the proportionality constant that relates pressure to moles for this vessel and explain what physical quantity this constant represents.
(c) Predict the pressure that would be observed if the vessel contained 0.65 mol of CH₄ under the same conditions.