Question 1: Define the chemical energy store and explain how energy is stored in chemical bonds.

Answer: The chemical energy store is the energy stored in the bonds of chemical substances. Energy is stored when chemical bonds are formed, and it is released when bonds are broken during chemical reactions.

Question 2: Describe a common everyday example where chemical energy is stored and later released.

Answer: A common example is a battery, where chemical energy is stored and later released as electrical energy when the chemical reactions occur inside it.

Question 3: In a combustion reaction, chemical energy is transformed into which other forms of energy?

Answer:

Question 4: Fill in the blank: When fuels like gasoline or coal are burned, the chemical energy stored in them is converted into __________ and __________.

Answer: heat, light

Question 5: Explain the importance of safety precautions when handling chemical fuels in practical experiments.

Answer: Safety precautions are crucial to prevent fires, explosions, and chemical burns. This includes wearing protective gear, working in well-ventilated areas, handling chemicals carefully, and ensuring proper storage and disposal.

Question 6: Calculate the amount of energy released when 2 moles of methane (CH₄) are burned, given that the enthalpy change of combustion is -890 kJ/mol.

Answer: 1780 kJ

Question 7: Identify the variables involved in designing an experiment to measure the energy released during a chemical reaction.

Answer: Variables include the type and amount of chemical used, temperature, pressure, and the method of measuring energy change.

Question 8: Describe one real-world application where understanding chemical energy stores is essential.

Answer: In designing batteries for electric vehicles, understanding how chemical energy is stored and converted into electrical energy is essential for efficiency and safety.

Question 9: Analyze the advantages and disadvantages of using chemical fuels compared to other forms of energy.

Answer: Advantages include high energy density and portability. Disadvantages involve pollution, finite resources, and safety risks during handling and storage. Alternative energy sources like solar or wind are renewable and cleaner but may be less reliable or require costly infrastructure.