Question 1: Latent heat is the energy absorbed or released by a substance during a change of phase, without changing its temperature. It is essential in processes such as melting, boiling, and condensation.

Answer: Latent heat is the energy involved in a phase change that does not change temperature.

Question 1: What is the main difference between sensible heat and latent heat?

Answer: Sensible heat causes a temperature change, while latent heat involves a phase change without temperature change.

Question 2: Explain why no temperature change occurs during the melting or boiling of a substance.

Answer: Because the energy is used to change the phase, not to increase temperature.

Question 1: Calculate the amount of heat energy required to convert 5 kg of ice at 0°C into water at 0°C. (Latent heat of fusion of ice = 334 kJ/kg)

Answer: 1670 kJ

Question 2: A container contains 2 kg of water at 100°C. How much energy is released when the water condenses into liquid water at the same temperature? (Latent heat of vaporization of water = 2260 kJ/kg)

Answer: 4520 kJ

Question 1: Design a simple experiment to measure the latent heat of vaporization of water. List the variables you would control and safety precautions to follow.

Answer: The experiment involves heating a known mass of water until it vaporizes, measuring the energy supplied (using a calorimeter or electrical heater), and calculating latent heat. Variables include mass of water, temperature, and energy supplied. Safety precautions include avoiding steam burns, using proper protective equipment, and ensuring electrical safety.

Question 1: A sample of sulfur is heated from 20°C to 115°C, and then it melts at 115°C. During the melting process, 500 J of energy is absorbed. What is the latent heat of fusion of sulfur per gram?

Answer: 10 J/g

Question 1: Explain in detail why large amounts of energy are required for the boiling of water compared to raising the temperature of water from 20°C to 80°C.

Answer: Boiling water requires energy to change the phase from liquid to gas, which involves overcoming intermolecular forces. This phase change involves latent heat, which is much higher than the energy needed to simply raise the temperature in the liquid phase.

Question 1: Name one industrial process that relies on latent heat and explain its importance.

Answer: Distillation relies on latent heat to separate mixtures based on boiling points, which is essential in producing pure substances and fuels.