Question 1: Define internal energy in the context of the particle model of matter.

Answer: Internal energy is the total kinetic and potential energy stored within the particles of a substance due to their random motion and interactions.

Question 2: Explain how increasing the temperature of a substance affects its internal energy.

Answer: Increasing the temperature increases the average kinetic energy of the particles, thereby raising the internal energy of the substance.

Question 3: What mechanisms allow internal energy to be transferred between objects?

Answer: Internal energy is transferred through conduction, convection, and radiation.

Question 4: Calculate the change in internal energy when 500 g of water is heated from 20°C to 80°C. (Specific heat capacity of water = 4200 J/kg°C).

Answer: Q = mcΔT; Q = 0.5 kg × 4200 J/kg°C × (80°C - 20°C) = 0.5 × 4200 × 60 = 126,000 Joules

Question 5: Identify two safety precautions when conducting experiments involving heating a substance to change its internal energy.

Answer: Use heat-resistant gloves and safety goggles; ensure proper ventilation and avoid overheating that could cause splattering or burns.

Question 6: A block of aluminum has a mass of 2 kg. How much energy is required to raise its temperature by 10°C? (Specific heat capacity of aluminum = 900 J/kg°C).

Answer: Q = mcΔT; Q = 2 kg × 900 J/kg°C × 10°C = 18,000 Joules

Question 7: Describe an experiment to measure the internal energy change of a gas when it is compressed. Include the key variables and safety considerations (theory only).

Answer: An experiment involves compressing a gas in a sealed cylinder with a movable piston while measuring temperature and pressure. Key variables include initial and final pressure, volume, and temperature. Safety precautions include avoiding over-pressurization, using a pressure relief valve, and handling equipment carefully to prevent leaks or ruptures.

Question 8: Analyze the scenario: A sealed container of sulfur is heated from 25°C to 75°C. The mass of sulfur is 0.1 kg, and its specific heat capacity is 700 J/kg°C. What is the increase in internal energy?

Answer: Q = mcΔT; Q = 0.1 kg × 700 J/kg°C × (75°C - 25°C) = 0.1 × 700 × 50 = 3,500 Joules

Question 9: Explain how internal energy is relevant to the design of thermal insulation in buildings.

Answer: Thermal insulation reduces heat transfer, thereby conserving internal energy within the building and maintaining desired temperatures efficiently.

Question 10: Identify a real-world technology or industry where understanding internal energy is crucial, and explain why.

Answer: In power plants, understanding internal energy is crucial for optimizing fuel combustion and energy transfer processes to generate electricity efficiently.