SL Physics Topic 3.1 and 3.2

Molecules in the solid state are able to

• vibrate.

• translate.

• rotate.

• move freely.

Iron melts at 1811 K. Which explains why liquid iron has more energy than solid iron if they're both at 1811 K?

• Liquid iron has more kinetic energy.

• Solid iron has more kinetic energy.

• Liquid iron has more potential energy.

• Solid iron has more potential energy.

Molten lava at its melting temperature comes into contact with water. The water quickly boils as the lava solidifies. Which of the following equations demonstrates the exchange of heat between the lava and the water as the lava solidifies. (The subscripts l and w stand for lava and water, respectively)

• |m_l⋅c_l⋅ΔT_l| = m_w⋅c_w⋅ΔT_w

• |m_l⋅c_l⋅ΔT_l| = m_w⋅c_w⋅ΔT_w + m_w⋅L_w

• m_l⋅L_l = m_w⋅c_w⋅ΔT_w + m_w⋅L_w

• m_l⋅L_l = m_w⋅L_w

Why doesn't the temperature change during a phase transition?

• It does it's just really hard to detect.

• All of the heat exchange is due to a change in potential energy.

• All of the heat exchange is due to a change in kinetic energy.

• All of the heat exchange is due to breaking chemical bonds.

The graph shows the variation of temperature and time for an substance. Which of the following is true?

• The melting point is 20 deg C.

• The specific heat capacity of the solid is greater than the specific heat capacity of the liquid.

• The specific heat capacity of the liquid is greater than the specific heat capacity of the solid.

• The latent heat of fusion is larger than the latent heat of vaporization.

The following graph depicts the temperature vs time for an unknown substance experience multiple phase transitions. Select all that are true.

• The latent heat of fusion is greater than the latent heat of vaporization.

• The latent heat of vaporization is greater than the latent heat of fusion.

• The specific heat capacity of the vapor is greater than the specific heat capacity of the liquid.

• The specific heat capacity of the liquid is greater than the specific heat capacity of the vapor.

A real gas approximates an ideal gas under high temperature and low pressure. Which of the following statements explains why this is true?

• At high temperature potential energy between molecules is high, and at low pressure the volume of the gas is very small.

• At high temperature potential energy between molecules is low, and at low pressure the volume of the container is very large compared to the volume of the gas.

• At high temperature kinetic energy of the molecules is very large and at low pressure the volume of the gas is also very large.

• At high temperature kinetic energy of the molecules is very large and at low pressure the volume of the container is very large compared to the volume of the gas.

The energy of the molecules of an ideal gas is

• a combination of potential and kinetic energies.

• only in the form of kinetic energy.

• only in the form of potential energy.

• only in the form of electric energy.

The pressure vs temperature of an ideal gas is depicted. What is the slope of this graph?

• nRV

• nRV^-1

• n^-1R^-1V

• nVR^-1

An ideal gas is compressed, causing its internal energy to increase. What happens to the temperature of the gas?

• Increases

• Decreases

• Stays constant

• Fluctuates