Outline the difference between the molecular structure of a solid and a liquid.

Using an appropriate error calculation, justify the number of significant figures that should be used for your answer to (c)(i).

Estimate the power input to the heating element. State an appropriate unit for your answer.

Two blocks, X and Y, are placed in contact with each other. Data for the blocks are provided.

X has a mass $m$. What is the mass of Y?

A.  $\frac{m}{4}$

B.  $m$

C.  $4 m$

D.  $6 m$

Distinguish between the internal energy of the oxygen at the boiling point when it is in its liquid phase and when it is in its gas phase.

Calculate, in kg, the mass of the gas.

What are the units of the ratio $\frac{\text{specific heat capacity of copper}}{\text{specific latent heat of vaporization of copper}}$?

A.     no units

B.     k

C.     k^–1

D.     k^–2

A mass $m$ of a liquid of specific heat capacity $c$ flows every second through a heater of power $P$. What is the difference in temperature between the liquid entering and leaving the heater?

A.  $\frac{mc}{P}$

B.  $273+\frac{mc}{P}$

C.  $\frac{P}{mc}$

D.  $273+\frac{P}{mc}$

A liquid of mass m and specific heat capacity c cools. The rate of change of the temperature of the liquid is k. What is the rate at which thermal energy is transferred from the liquid?

A. $\frac{mc}{k}$

B. $\frac{k}{mc}$

C. $\frac{1}{kmc}$

D. kmc

State the unit for the quantity represented by the gradient in your answer to (b)(i).

Some of the gravitational potential energy transferred into internal energy of the skis, slightly increasing their temperature. Distinguish between internal energy and temperature.

The graph shows how the temperature of a liquid varies with time when energy is supplied to the liquid at a constant rate P. The gradient of the graph is K and the liquid has a specific heat capacity c.

What is the mass of the liquid?

A.     $\frac{P}{cK}$

B.     $\frac{PK}{c}$

C.     $\frac{Pc}{K}$

D.     $\frac{cK}{P}$

Distinguish between the internal energy of the oxygen at the boiling point when it is in its liquid phase and when it is in its gas phase.

The mass of the resistance wire is 0.61 g and its observed temperature rise is 28 K. Estimate the specific heat capacity of the wire. Include an appropriate unit for your answer.

Outline whether your answer to (a) is likely to overestimate or underestimate the power input.

A bicycle of mass $M$ comes to rest from speed $v$ using the back brake. The brake has a specific heat capacity of $c$ and a mass $m$. Half of the kinetic energy is absorbed by the brake.

What is the change in temperature of the brake?

A.  $\frac{M{v}^2}{4mc}$

B.  $\frac{M{v}^2}{2mc}$

C.  $\frac{m{v}^2}{4Mc}$

D.  $\frac{m{v}^2}{2Mc}$

Calculate the mass of the oil that remains unfrozen after $60$ minutes.

Estimate the specific latent heat of vaporization of water. State an appropriate unit for your answer.

The heater is removed and a mass of 0.30 kg of pasta at −10 °C is added to the boiling water.

Determine the equilibrium temperature of the pasta and water after the pasta is added. Other heat transfers are negligible.

Specific heat capacity of pasta = 1.8 kJ kg⁻¹ K⁻¹
Specific heat capacity of water = 4.2 kJ kg⁻¹ K⁻¹

Calculate the thermal energy transferred from the sample during the first $30$ minutes.

Estimate the specific heat capacity of the oil in its liquid phase. State an appropriate unit for your answer.

A piece of metal at a temperature of $100 °\text{C}$ is dropped into an equal mass of water at a temperature of $15 °\text{C}$ in a container of negligible mass. The specific heat capacity of water is four times that of the metal. What is the final temperature of the mixture?

A.  $83 °\text{C}$

B.  $57 °\text{C}$

C.  $45 °\text{C}$

D.  $32 °\text{C}$

When 40 kJ of energy is transferred to a quantity of a liquid substance, its temperature increases by 20 K. When 600 kJ of energy is transferred to the same quantity of the liquid at its boiling temperature, it vaporizes completely at constant temperature. What is

$\frac{\text{specific latent heat of vaporization}}{\text{specific heat capacity of the liquid}}$

for this substance?

A. 15 K⁻¹

B. 15 K

C. 300 K⁻¹

D. 300 K

Determine the energy required to melt all of the ice from –20 °C to water at a temperature of 0 °C.

Specific latent heat of fusion of ice  = 330 kJ kg^–1
Specific heat capacity of ice            = 2.1 kJ kg^–1 k^–1
Density of ice                                = 920 kg m^–3

An insulated tube is filled with a large number n of lead spheres, each of mass m. The tube is inverted s times so that the spheres completely fall through an average distance L each time. The temperature of the spheres is measured before and after the inversions and the resultant change in temperature is ΔT.

What is the specific heat capacity of lead?

A. $\frac{sgL}{nm\mathrm{\Delta }T}$

B. $\frac{sgL}{\mathrm{\Delta }T}$

C. $\frac{sgL}{n\mathrm{\Delta }T}$

D. $\frac{gL}{m\mathrm{\Delta }T}$

Determine the atmospheric pressure. Give a suitable unit for your answer.

At the instant of impact the meteorite which is made of ice has a temperature of 0 °C. Assume that all the kinetic energy at impact gets transferred into internal energy in the meteorite. Calculate the percentage of the meteorite’s mass that melts. The specific latent heat of fusion of ice is 3.3 × 10⁵ J kg^–1.

An insulated container of negligible mass contains a mass 2M of a liquid. A piece of a metal of mass M is dropped into the liquid. The temperature of the liquid increases by 10 °C and the temperature of the metal decreases by 80 °C in the same time.

What is $\frac{\text{specific heat capacity of the liquid}}{\text{specific heat capacity of the metal}}$?

A.  2

B.  4

C.  8

D.  16

Estimate the power, in kW, that is available from the plutonium at launch.

The mass of the wire is 18 g. The specific heat capacity of copper is 385 J kg⁻¹ K⁻¹. Estimate the increase in temperature of the wire.

Show that the mass of a nitrogen molecule is 4.7 × 10⁻²⁶ kg.

Discuss, with reference to the molecules in the liquid, the difference between milk at 11 °C and milk at 84 °C.