Ideal Gases · Paper 1 — Free Chemistry HL Practice Questions

A fixed amount of nitrogen gas is maintained at 298 K. A student plots pressure $P$ against $\dfrac{1}{V}$ and obtains a straight line passing through the origin. Which conclusion is consistent with this observation?

A weather balloon contains $0.50\ \text{mol}$ of helium gas at $101\ \text{kPa}$ and $300\ \text{K}$. The balloon rises to an altitude where the pressure is $50\ \text{kPa}$ and the temperature is $250\ \text{K}$. Which statement correctly describes the change in volume of the balloon?

A student uses the ideal gas equation $PV = nRT$ to determine the molar mass of an unknown gas. She measures the mass of a sample and its volume at $101\ \text{kPa}$ and $298\ \text{K}$, obtaining a molar mass of $44\ \text{g mol}^{-1}$. Which gas is most consistent with this result?

A sample of nitrogen gas occupies $250 \text{ cm}^3$ at $101 \text{ kPa}$ and $25 \text{ °C}$. It is transferred into a sealed container of volume $500 \text{ cm}^3$ at the same temperature. What is the pressure of the gas in the new container?