Question 1: Define what is meant by a chemical energy store in physics.

Answer: A chemical energy store is the form of energy stored within the bonds of chemical substances, which can be released during chemical reactions.

Question 2: Explain how chemical energy is stored and how it can be released during a reaction.

Answer: Chemical energy is stored in the bonds between atoms in molecules. When chemical reactions occur, these bonds are broken and formed again, releasing or absorbing energy. In exothermic reactions, energy is released into the surroundings, often as heat or light.

Question 3: Identify three common examples of chemical energy stored in everyday products or processes.

Answer: Batteries, food, and fuels such as petrol and natural gas.

Question 4: A car engine uses chemical energy stored in fuel. What type of energy store is this an example of?

Answer: Chemical

Question 5: Fill in the blank: When fuels like petrol are burned in a car engine, the chemical energy is converted into __________ and kinetic energy.

Answer: heat

Question 6: Describe a simple experiment to show that chemical reactions can produce heat energy.

Answer: Mixing vinegar and baking soda produces a chemical reaction that releases heat. Students can observe the temperature increase using a thermometer, demonstrating heat energy release during the reaction.

Question 7: Discuss two safety precautions to consider when working with chemical reactions that release energy in a school laboratory.

Answer: Always wear safety goggles and gloves to protect against splashes or spills. Conduct reactions in a well-ventilated area or under a fume hood to avoid the buildup of harmful gases.

Question 8: A scenario describes a battery powering a flashlight. How does this demonstrate chemical energy being converted into light and electrical energy?

Answer: The battery's chemical energy is converted into electrical energy when the circuit is complete, and this electrical energy then powers the bulb, converting into light energy.

Question 9: Explain why chemical energy is considered a renewable energy source compared to fossil fuels.

Answer: Chemical energy in renewable sources like biofuels or batteries can be replenished continuously, whereas fossil fuels are finite resources formed over millions of years and are depleted faster than they are naturally replenished.

Question 10: In industry, chemical energy is used in processes such as the production of electricity via fuel cells. Briefly describe how fuel cells convert chemical energy into electrical energy.

Answer: Fuel cells convert chemical energy directly into electrical energy through electrochemical reactions. When a fuel like hydrogen reacts with oxygen in the fuel cell, it produces electricity, water, and heat, with no combustion involved, making it an efficient energy conversion process.