Question 1: Chemical energy is stored in the bonds of chemical compounds. When these bonds are broken during a chemical reaction, energy is released or absorbed. This stored energy can be harnessed in various engineering applications such as batteries and fuel cells.

Answer: Chemical energy is stored in the bonds of chemical compounds and is released or absorbed during chemical reactions.

Question 1: Define chemical energy.

Answer: Stored energy in the bonds of chemical compounds.

Question 2: Explain how a battery uses chemical energy to produce electrical energy.

Answer: A battery uses chemical energy stored in its chemicals; during a chemical reaction, this energy is released and converted into electrical energy to power devices.

Question 1: A fuel cell releases 150 kJ of energy during a reaction. If the reaction involves 2 moles of hydrogen, calculate the energy released per mole of hydrogen. (Use the formula: Energy per mole = Total energy / number of moles).

Answer: 75 kJ per mole

Question 1: Describe a simple experimental method to measure the amount of chemical energy released in a reaction involving a hydrocarbon fuel. Include safety precautions.

Answer: Burn a known mass of the hydrocarbon under a calorimeter to measure temperature change. Use safety equipment like goggles and gloves, conduct in a well-ventilated area, and ensure proper handling of hot equipment and gases.

Question 1: A certain chemical reaction in an industrial process releases 500 kJ of energy per kilogram of reactant. If a factory uses 200 kg of reactant daily, estimate the total energy released in a day.

Answer: 100,000 kJ

Question 1: Explain the role of chemical energy in the operation of a fuel cell vehicle. (6 marks)

Answer: A fuel cell vehicle converts chemical energy stored in hydrogen into electrical energy through a chemical reaction with oxygen. This electrical energy powers the electric motor, producing zero emissions. The process involves catalysts and electrochemical reactions that improve efficiency, making fuel cells a promising technology for cleaner transportation.

Question 1: Identify two engineering devices or systems that utilise chemical energy stores and describe how they work.

Answer: Batteries store chemical energy which is converted into electrical energy when in use. Internal combustion engines convert chemical energy in fuels like petrol into mechanical energy to power vehicles.