Ijmb Model Questions Vol1 2022 Biology Question 4

The rate of respiration in germinating beans is being investigated by measuring the volume of carbon dioxide (CO₂) evolved in a sealed respiration chamber. The procedure is: 1. Weigh 5.00 g of dry beans, soak them in water for 12 h, then place the soaked beans in a 250 mL airtight chamber containing 150 mL of distilled water. 2. The chamber is kept at a constant temperature and the CO₂ produced displaces water in a graduated tube. 3. The volume of displaced water is recorded after 30 min. Two experiments are performed at different temperatures. Data: - At 25 °C: displaced water volume = 12.5 mL. - At 35 °C: displaced water volume = 18.2 mL. Atmospheric pressure = 760 mmHg. Water‑vapour pressure: 23.8 mmHg at 25 °C and 38.0 mmHg at 35 °C. Assume ideal gas behaviour (R = 0.0821 L·atm·mol⁻¹).