Question

1. (a) What name is given to the law describing the relationship between volume and pressure at constant temperature? Write a mathematical expression that describes this relationship. (2 marks)

(b) Sketch a graph of the relationship described in part (a).
(2 marks)

(c) O2 gas is transferred from a 3 L vessel containing oxygen at 4 atm to an evacuated 20 L vessel at a constant temperature of 350 K. What is the pressure inside the 20 L vessel after the transfer? (2 marks)

(d) 5 g of H2 gas is subsequently transferred into the vessel at 350 K. What is the partial pressure of H2 gas inside the vessel? (3 marks)


(e) The mixture of H2 and O2 gases is ignited. Afterwards, the reaction vessel and its contents are cooled to 350 K. The total pressure inside the vessel was measured to be 2.77 atm. What is the vapour pressure of water at this temperature? (Assume that liquid water has negligible volume.) (6 marks)


(f) Explain the term ‘mole fraction’ (χi) and show, by use of an equation, how it is calculated. (2 marks)

(g) The mole fraction of O2 in atmospheric air is 0.21. Calculate the concentration of O2 in a sample of atmospheric air in a 10 L container at a pressure of 650 mmHg and temperature of 160 °C.

Answer 1