Question

A piece of iron is placed in a kiln until it reaches the temperature θ of the kiln. The iron is then quickly transferred to water held in a [4 marks] thermally insulated container. The water is stirred until it reaches a steady temperature. The following data are available.

Thermal capacity of the piece of iron = 60JK
Thermal capacity of the water = 2.0×10 JK
Initial temperature of the water = 16°C
Final temperature of the water = 45°C

The thermal capacity of the container and insulation is negligible.
(i) State an expression, in terms of θ and the above data, for the energy transfer of the iron in cooling from the temperature of the kiln to the
final temperature of the water.
(ii) Calculate the increase in internal energy of the water as the iron cools in the water.
(iii) Use your answers to (c)(i) and (c)(ii) to determine θ.

Answer 1

Explanation:

A piece of iron is placed in a kiln until it reaches the temperature θ

of the kiln. The iron is then quickly transferred to water held in a

thermally insulated container. The water is stirred until it reaches a

steady temperature. The following data are available.

Thermal capacity of the piece of iron = 60 J K–1

Thermal capacity of the water = 2.0 × 103

J K–1

Initial temperature of the water = 16 °C

Final temperature of the water = 45 °C

The thermal capacity of the container and insulation is negligible.

A piece of iron is placed in a kiln until it reaches the temperature θ

of the kiln. The iron is then quickly transferred to water held in a

thermally insulated container. The water is stirred until it reaches a

steady temperature. The following data are available.

Thermal capacity of the piece of iron = 60 J K–1

Thermal capacity of the water = 2.0 × 103

J K–1

Initial temperature of the water = 16 °C

Final temperature of the water = 45 °C

The thermal capacity of the container and insulation is negligible.

The internal volume of a gas cylinder is 2.0

× 10–2 m3

. An ideal gas is pumped into the

cylinder until the pressure becomes 20 MPa

at a temperature of 17°C.

Determine the number of gas atoms in the

cylinder.

The graph shows a pressure-volume (P–V) relationship for

a fixed mass of an ideal gas.

The gas undergoes

a three-stage cycle

AB, BC and CA.

Use data from the graph to show that the change AB is

isothermal.

The graph shows a pressure-volume (P–V) relationship for

a fixed mass of an ideal gas.

The gas undergoes

a three-stage cycle

AB, BC and CA.