# Specification focus questions on Ideal Gas Molecules – Pearson’s Edexcel IGCSE Physics

## Questions

What is the random motion of molecules in a gas?

How do the molecules in a gas exert a force on the walls of a container?

What is the absolute zero of temperature and why is it important?

How does the Kelvin scale of temperature differ from the Celsius scale?

Can you convert between the Kelvin and Celsius scales?

Why does an increase in temperature result in an increase in the average speed of gas molecules?

How is the Kelvin temperature of a gas related to the average kinetic energy of its molecules?

What is the relationship between pressure and volume at constant temperature for a fixed amount of gas?

What is the relationship between pressure and Kelvin temperature at constant volume for a fixed amount of gas?

What is the relationship between the pressure and Kelvin temperature of a fixed mass of gas at constant volume?

Can you use the relationship between the pressure and Kelvin temperature of a fixed mass of gas at constant volume to solve problems?

What is the relationship between the pressure and volume of a fixed mass of gas at constant temperature?

Can you use the relationship between the pressure and volume of a fixed mass of gas at constant temperature to solve problems?

How does the random motion of gas molecules result in pressure?

Why does increasing the temperature of a gas result in an increase in pressure?

Can you explain the difference between the Celsius and Kelvin scales?

What is the importance of understanding the relationships between pressure, volume, and temperature in gases?

How is the average kinetic energy of gas molecules related to the Kelvin temperature?

Why is the absolute zero of temperature considered to be a theoretical limit?

Can you give an example of how the relationships between pressure, volume, and temperature in gases can be applied in real-life situations?

The random motion of molecules in a gas refers to the constant, random movement and collision of individual gas molecules with each other and with the walls of a container.

The molecules in a gas exert a force on the walls of a container due to their random motion and collisions with the walls. This force is known as pressure.

The absolute zero of temperature is the theoretical minimum temperature that can be reached, where all matter has no internal energy or thermal motion. It is important because it serves as a reference point for temperature measurements and helps to define the Kelvin temperature scale.

The Kelvin scale of temperature is based on the idea of absolute zero, and it is an absolute temperature scale. It is different from the Celsius scale in that 0 K is the absolute zero of temperature, while 0°C is the freezing point of water.

Yes, it is possible to convert between the Kelvin and Celsius scales by adding or subtracting a constant value. The conversion formula is T(K) = T(°C) + 273.15.

An increase in temperature results in an increase in the average speed of gas molecules because thermal energy is added to the system, which results in an increase in the kinetic energy of the gas molecules.

The Kelvin temperature of a gas is proportional to the average kinetic energy of its molecules. The more energy the molecules have, the higher the temperature of the gas.

For a fixed amount of gas, the relationship between pressure and volume at constant temperature is described by Boyle’s Law, which states that the pressure and volume of a gas are inversely proportional.

For a fixed amount of gas, the relationship between pressure and Kelvin temperature at constant volume is described by Gay-Lussac’s Law, which states that the pressure and temperature are directly proportional.

The relationship between the pressure and Kelvin temperature of a fixed mass of gas at constant volume is described by the Ideal Gas Law, which states that the pressure and temperature are proportional, provided that the volume of the gas is constant.

Yes, the relationship between the pressure and Kelvin temperature of a fixed mass of gas at constant volume can be used to solve problems, such as calculating the pressure of a gas at a given temperature, or vice versa.

The relationship between the pressure and volume of a fixed mass of gas at constant temperature is described by Charles’ Law, which states that the volume and temperature of a gas are directly proportional, provided that the pressure of the gas is constant.

Yes, the relationship between the pressure and volume of a fixed mass of gas at constant temperature can be used to solve problems, such as calculating the volume of a gas at a given pressure, or vice versa.

The random motion of gas molecules results in pressure due to the collisions of the molecules with the walls of a container. These collisions transfer energy from the gas molecules to the walls, which causes the pressure to increase.

Increasing the temperature of a gas results in an increase in pressure because the added thermal energy increases the kinetic energy of the gas molecules, causing them to collide with the walls of the container more frequently and with greater force.

The Celsius scale measures temperature relative to the freezing and boiling points of water, while the Kelvin scale is an absolute temperature scale based on the idea of absolute zero.

The average kinetic energy of gas molecules is proportional to the Kelvin temperature of the gas. As the temperature of a gas increases, the average kinetic energy of its molecules also increases, leading to a higher Kelvin temperature.

The absolute zero of temperature, which is -273 °C, is considered to be a theoretical limit because it is the temperature at which all molecular motion should cease and the gas should have no internal energy. However, in reality, it is impossible to achieve absolute zero temperature because of the presence of residual molecular motion.

Real-life examples of the relationships between pressure, volume, and temperature in gases include the behaviour of gas in a car tire, the operation of a gas-powered engine, the behaviour of gases in a pressure cooker, and the functioning of a gas refrigerator. These relationships are used to understand and control the behaviour of gases in various industrial and everyday applications.