物質的粒子模型：練習題

The specific heat capacity of aluminum is \( 900\text{ J/kg}^{\circ}\text{C} \). How much energy is required to raise the temperature of \( 2\text{ kg} \) of aluminum by \( 10\text{ }^{\circ}\text{C} \)?

A student heats \( 1\text{ kg} \) of water with a \( 2\text{ kW} \) electric kettle. If the water's initial temperature is \( 20\text{ }^{\circ}\text{C} \) and the specific heat capacity of water is \( 4200\text{ J/kg}^{\circ}\text{C} \), how long will it take to reach \( 100\text{ }^{\circ}\text{C} \)? (Assume \( 100\% \) efficiency).

Calculate the total energy required to turn \( 0.2 \, \text{kg} \) of ice at \( 0 \, ^\circ\text{C} \) into water at \( 10 \, ^\circ\text{C} \).
(Specific latent heat of fusion of ice = \( 334,000 \, \text{J/kg} \); Specific heat capacity of water = \( 4200 \, \text{J/kg}^\circ\text{C} \))

What is the specific latent heat of vaporisation of a substance?

Which of the following factors would decrease the rate of evaporation of a liquid from an open container?

A block of iron with a mass of \( 2.5 \text{ kg} \) is heated from \( 20^\circ\text{C} \) to \( 50^\circ\text{C} \). Calculate the energy required for this temperature change.
(Specific heat capacity of iron = \( 450 \text{ J/kg}^\circ\text{C} \))

Explain, in terms of the kinetic theory and density, why a liquid expands and becomes less dense when it is heated, eventually leading to the formation of a convection current.

A student has a sample of a solid substance. Describe the arrangement and movement of the particles in this solid state according to the kinetic theory.

A student uses the kinetic theory to investigate the properties of different states of matter. Based on this theory, answer the following questions:

a. Describe the arrangement and movement of particles in a solid and a gas.
b. A substance with a mass of \( 0.5 \text{ kg} \) is heated, and its temperature increases by \( 20^\circ\text{C} \). If the specific heat capacity of the substance is \( 4200 \text{ J/kg}^\circ\text{C} \), calculate the energy required for this temperature change.
c. Name the process that occurs when a liquid turns into a gas at its boiling point and explain the energy change involved in terms of the particles.

A student carries out an experiment to investigate the thermal properties of an unknown solid substance with a mass of \( 0.8 \text{ kg} \). The substance is heated from a solid state at room temperature until it becomes a gas. The following data was recorded during the heating process:
- Energy supplied to raise the temperature from \( 20^\circ\text{C} \) to its melting point of \( 80^\circ\text{C} \): \( 57,600 \text{ J} \).
- Energy supplied to completely melt the solid at \( 80^\circ\text{C} \): \( 120,000 \text{ J} \).
- Energy supplied to boil the liquid into a gas at its boiling point: \( 640,000 \text{ J} \).

a. Calculate the specific heat capacity of the substance in its solid state. State the equation you use.
b. Calculate the specific latent heat of fusion for this substance.
c. Calculate the specific latent heat of vaporisation for this substance.
d. Use the kinetic theory to explain why the temperature of the substance remains constant at \( 80^\circ\text{C} \) while it is melting, even though energy is still being supplied.