Question 1: Oxygen evolution is the process by which oxygen is produced, primarily through photosynthesis in plants. During photosynthesis, plants convert carbon dioxide and water into glucose and oxygen, driven by sunlight. This process has been crucial for maintaining Earth's atmosphere and supporting aerobic life.

Answer: Oxygen evolution is the production of oxygen during photosynthesis, where plants convert CO₂ and H₂O into glucose and O₂ using sunlight.

Question 1: Define 'photosynthesis' and explain its role in oxygen evolution.

Answer: Photosynthesis is the process by which green plants convert light energy into chemical energy, producing glucose and oxygen. It is the main source of oxygen in Earth's atmosphere.

Question 2: Describe the role of chlorophyll in oxygen evolution during photosynthesis.

Answer: Chlorophyll absorbs sunlight, providing energy to drive the reactions that split water molecules to produce oxygen.

Question 1: Explain the role of water molecules in oxygen evolution in photosynthesis.

Answer: Water molecules are split by light energy in the light-dependent reactions, releasing oxygen, protons, and electrons.

Question 2: What is the name of the process where water molecules are split during photosynthesis?

Answer: Photolysis

Question 1: A laboratory experiment shows that a plant produces 0.5 litres of oxygen gas per hour under certain conditions. Calculate the volume of oxygen produced in 24 hours.

Answer: 12 litres

Question 2: If 2 grams of water are split during photosynthesis, how many moles of oxygen are produced? (Molar mass of H₂O = 18 g/mol, O₂ = 32 g/mol).

Answer: 0.111 moles

Question 1: Design a simple experiment to measure the rate of oxygen evolution in pondweed when exposed to different light intensities. Include variables to control and safety precautions.

Answer: Students can set up pondweed in water with a test tube inverted over it, exposing it to varying light intensities. The volume of oxygen produced can be measured over time. Variables include light intensity, temperature, and water quality. Safety precautions include handling water and ensuring electrical equipment is dry.

Question 1: A set of data shows that increasing light intensity increases oxygen production up to a point, after which additional light has no effect. Explain this observation in terms of photosynthesis.

Answer: Initially, higher light intensity increases the rate of photosynthesis and oxygen production. However, beyond a certain point, the enzymes involved become saturated, and the rate levels off due to limiting factors like CO₂ availability.

Question 1: Describe how artificial photosynthesis could be used to generate oxygen and renewable energy.

Answer: Artificial photosynthesis mimics natural processes to produce oxygen and organic compounds or fuels using sunlight, water, and catalysts, offering sustainable energy and oxygen production.

Question 2: Explain the significance of oxygen evolution in environmental and industrial contexts.

Answer: Oxygen evolution is essential for maintaining breathable atmospheres, supporting aquatic life, and enabling industries such as water treatment and renewable energy technologies like solar fuel cells. Understanding and harnessing this process can lead to sustainable solutions for environmental challenges.