IB Final Review Topic 3

The specific latent heat of fusion of a substance is defined as the amount of thermal energy required to change the phase of 

• the substance at constant temperature. 
• unit mass of the substance to liquid at constant temperature. 
• unit mass of the substance at constant temperature. 
• the substance to gas at constant temperature. 

A fixed mass of an ideal gas is heated at constant volume. Which one of the following graphs best shows the variation of Celsius temperature t with pressure p of the gas? 

• A
• B
• C
• D

The ratio 

• does not have any unit. 
• has unit J kg⁻¹K⁻¹ . 
• has unit J kg⁻¹ . 
• has unit kg. 

Tags

NGSS.HS-PS3-4

In the molecular kinetic theory of ideal gases, it is assumed that

• the forces between the molecules of the gas and the container are always zero. 
• the intermolecular potential energy of the molecules of the gas is constant. 
• the kinetic energy of a given molecule of the gas is constant. 
• the momentum of a given molecule of the gas is constant. 

The distance between the 0°C and 100°C marks on a mercury-in-glass thermometer is 20 cm. When the thermometer bulb is placed in a mixture of ice and salt, the mercury level is 4 cm below the 0°C mark. The temperature of the mixture is 

• +20 °C . 
• +5°C. 
• −5°C. 
• −20 °C . 

Tags

NGSS.MS-PS1-4

Some liquid is contained in a shallow dish that is open to the atmosphere. The rate of evaporation of the liquid does not depend on 

• the temperature of the liquid. 
• the temperature of the atmosphere. 
• the depth of the liquid. 
• the pressure of the atmosphere. 

The equation of state for an ideal gas, pV = nRT, describes the behaviour of real gases 

• only at low pressures and large volumes. 
• only at high temperatures. 
• only at large volumes and large pressures. 
• at all pressures and volumes. 

The temperature of an ideal gas is reduced. Which one of the following statements is true? 

• The molecules collide with the walls of the container less frequently. 
• The molecules collide with each other more frequently. 
• The time of contact between the molecules and the wall is reduced. 
• The time of contact between molecules is increased. 

Two objects near each other are at the same temperature. Which of the following statements has to be true? 

• The objects have the same internal energy. 
• The objects have the same thermal capacity. 
• No thermal energy is exchanged between the objects. 
• The net thermal energy exchanged between the objects is zero. 

The temperature of an ideal gas is a measure of the molecules’ average 

• velocity. 
• momentum. 
• kinetic energy. 
• frequency of collisions. 

Tags

NGSS.HS-PS3-2