WorksheetsTopic11-specific heat capacity,latent heat,melting,boiling,evapo
Total questions: 47
Worksheet time: 24mins
What is a unit of specific latent heat?
J
J/g
J °C
J/(g°C)
For a given liquid at atmospheric pressure, which process can occur at any temperature?
Evaporation
Boiling
Melting
Solidification
Which statement describes the boiling of water?
It occurs at a fixed temperature and only on the surface
It occurs at a fixed temperature and throughout the liquid
It occurs at any temperature and only on the surface
It occurs at any temperature and throughout the liquid
Which of the following statements is correct?
There must be an increase in temperature if there is no change of state.
There must be an increase of temperature if there is a change of state.
Temperature will remain constant.
Thermal equilibrium is reached with the environment.
What is the name given to the amount of energy needed to turn 1 kg of water at 100 C into steam at 100 °C?
heat capacity
latent heat
specific heat capacity
specific latent heat
An electric kettle with a 2000 W heater contains 0.25 kg of boiling water. What time will it take before all the water has boiled away? (The specific latent heat for steam=2.0 MJ/kg.)
250 s
4000 s
1000 s
16 000s
A kettle has a rating 1200 W, 240 V. The heat capacity of water is 4.2 J K-I gr'. What is the time taken to increase the temperature of 1.0 kg of water from 20 °C to 50 °C?
3.5 mins
210 mins
35 mins
12600 mins
Which statement about the evaporation and boiling of a liquid is correct?
Boiling always occurs at a higher temperature than evaporation
Evaporation occurs at any temperature, but the boiling point depends on the external pressure.
Evaporation results in the loss of the most energetic molecules from a liquid but, in boiling, all molecules have the same energy.
The rates of evaporation and boiling are unaffected by changes in the surface area of the liquid.
What happens when liquid is being heated at its boiling point?
an increase in molecular size
an increase in molecular spacing
an increase in the average kinetic energy of the molecules
an increase in the total number of molecules
What is meant by the term specific heat capacity of a substance?
The thermal energy required to change the state of 1 kilogram of the substance.
The thermal energy required to change the state of the substance without change of temperature.
The thermal energy required to raise the temperature of 1 kilogram of the substance by 1 Kelvin.
The thermal energy required to raise the temperature of the substance by 1 Kelvin.
Latent heat of vaporisation is the energy required
to separate the molecules of the liquid
to increase the average molecular speed in the liquid phase to that in the gas phase.
to separate the molecules and to increase the average molecular speed to that in the gas phase.
to separate the molecules and to force back the atmosphere.
Heat capacity and specific heat capacity have different definition. Which statement describes the difference?
heat capacity involves 1 kg of material, specific heat capacity does not.
heat capacity involves a change in temperature of 1 C, specific heat capacity does not
specific heat capacity involves 1 kg of material, heat capacity does not.
specific heat capacity involves a change in temperature of 1 "C, heat capacity does not
The specific heat capacity of copper is 400 J/kg. A 2 kg mass of copper is heated for 40 s by a 100 W heater. What is the maximum possible rise in temperature?
5 °C
10°C
20°C
50 °C
Two blocks of paraffin A and B are at the same temperature. The masses of A and B are 1.0 kg and 2.0 kg respectively. They are then immersed in a heat bath. Why does A melt faster than B?
A is denser than B.
A is less dense than B
A has a smaller mass.
A has a smaller specific heat capacity.
The energy required to change liquid water into water vapour at the same temperature is called latent heat of vaporisation. What does this energy do?
increases the average separation of the water molecules
increases the average speed of the water molecules
raises the temperature of the air near the water
splits the water molecules into their separate atoms
The bulb of a thermometer is wrapped in a tub of cotton fabric. The fabric is dipped into water at room temperature and left for some time. The thermometer wrapped in wet fabric is then removed and evaporation takes place. What happens to the thermometer reading?
It falls.
It remains unchanged.
It rises.
It rises and then falls
The heat capacity of chromium at room temperature is 24 JK^-1 Its mass is 52 g. What is the specific heat capacity of chromium?
0.46 J kg^-1 K^-1
2.2 J kg^-1 K^-1
460 J kg^-1 K^-1
1200 kg^-1 K^-1
Heat energy is supplied at the same rate to 100 g of paraffin and to 100 g of water in similar containers. Why does the temperature of the paraffin rise more quickly?
The paraffin has a larger specific heat capacity than water
The paraffin has a smaller specific heat capacity than water.
The paraffin is less dense than water.
The paraffin is more dense than water.
An electric kettle contains 1.5 kg of water at 100 °C and is powered by a 2.0 kW electric element. If the thermostat of the kettle fails to operate, approximately how long will the kettle take to boil dry? [Take the specific latent heat of vaporisation of water as 2000 kJ kg^-1]
500 s
1500 s
1000 s
3000 s
In an experiment, 1700 J of thermal energy (heat) is used to heat 8.0 g of ice at 0 °C. Assume that water from the melted ice remains at 0 °C. How much ice remains after heating? (specific latent heat of fusion of ice 340 J/g)
0
5.0 g
3.0 g
7.8 g
A 2 kW kettle containing boiling water is placed on a balance. It is left there and continues to boil for 5 minutes. The balance reading changes by 0.2 kg. What does this information give as an estimate for the specific latent heat of vaporisation of water?
2000 J/kg
50 000 J/kg
3000 J/kg
3 000 000 J/kg
A 2 kg mass of copper is heated for 40 s by a heater that produces 100 J/s. The specific heat capacity of copper is 400 J/ (kg K). What is the rise in temperature?
5 K
10 K
20 К
50 K
Which of the following materials has the lowest specific heat capacity if the rate of heat supply is the same?
A
B
C
D
In an experiment, 1700 J of thermal energy (heat) is supplied to 8.0 g of ice at 0 "C. Assume that water from the melted ice stays at 0 °C. The specific latent heat of fusion of ice is 340 J/g. How much ice remains?
0
5.0 g
3.0 g
7.8 g
A 2 kW kettle containing boiling water is placed on a balance, It is left there and continues to boil for 5 minutes. The balance reading changes by 0.2 kg. What does this information give as a value for the specific latent heat of vaporisation of water?
2000 J/kg
3000 J/kg
50000 J/kg
3 000 000 J/kg
A hand dryer blows out hot air. In one second, 75 g of air enters the hand dryer and the air gains 2000 J of thermal energy. The specific heat capacity of air is 1.1 J/(g °C). Which expression gives the temperature rise of the air as it passes through the hand dryer?
75/(1.1 x 2000) °C
(75 x 1.1)/2000 °C
2000/(1.1 x 75) °C
(2000 x 1.1)/75 °C
Some ice cubes are taken from a deep-freeze and placed in a metal container. The container is heated a steady rate and temperature /time readings are taken. The results are recorded on a graph. Which temperature corresponds to 0 °C?
A
B
C
D
A solid is heated at a constant rate. The graph shows how its temperature changes as it heats up. Which processes are taking place at region Y?
Boiling and evaporation
Condensation only
Evaporation only
Solidification and evaporation
A hot liquid is carefully poured into a beaker. The graph shows how its temperature changes as it cools towards room temperature. Which processes are taking place at region X?
boiling and evaporation
condensation only
evaporation only
solidification and evaporation
Some ice is placed in a beaker and is heated until the beaker contains boiling water. The graph shows the temperature of the beaker and its contents during the experiment. Between which two points on the graph does the beaker contain a mixture of solid and liquid?
V and W
W and X
X and Y
Y and Z
The diagram shows the melting points and boiling points of four substances. (X = melting point, dot = boiling point.) Which substance is a gas at 150 °C and a solid at -50 °C?
A
B
C
D
In a boiling experiment, energy is supplied at a constant rate to a liquid in a beaker of negligible heat capacity. The temperature of the liquid rises at 4.0 K per minute just before it begins to boil. After 40 minutes all the liquid has boiled away. For this liquid, what is the ratio of
specific heat capacity/specific latent heat of vaporisation ?
1/10 K^-1
1/40 K^-1
1/160 K^-1
1/640 K^-1
Four beakers containing the same amount of water at the same temperature are placed on hot metal plates. The lower surfaces of the metal plates are kept at the same temperature. The plates are all the same size but are made from four different metals. The times taken to produce stated temperature rises are given below. Which metal is the poorest conductor?
A
B
C
D
A substance is heated in an enclosed space until it becomes a gas. After the heater is removed, the temperature is recorded at regular intervals. The graph shows temperature plotted against time. What does the section PQ represent?
boiling
condensing
melting
solidifying
The diagrams represent two blocks of copper, P and Q, each receiving the same amount of energy W. The mass of P is twice the mass of Q. The temperature rise of P is half the temperature rise of Q. Which statement about P and Q is correct?
The heat capacity of P is half the heat capacity of Q
The heat capacity of P is twice the heat capacity of Q.
The specific heat capacity of P is half the specific heat capacity of Q
The specific heat capacity of P is twice the specific heat capacity of Q
In the experiment shown, the amount of electrical energy used to melt some ice is measured using a joulemeter. To find the specific latent heat of fusion of the ice, what must also be measured?
the mass of water produced by melting ice
the temperature change of the ice
the time taken for the ice to melt
the voltage of the electrical supply
Ice at -10 °C is heated at a constant rate until it is water at +10°C. Which graph shows how the temperature changes
with time?
The motion of the molecules of two gases causes them to mix. What is this mixing called?
conduction
convection
diffusion
evaporation
Which of the following expands most when its temperature is raised by 10 K (°C)?
10 cm^3 of air
10 cm^3 of copper
10 cm^3 of ice
10 cm^3 of water
Which of the following increase when a liquid becomes a gas at its boiling point?
the average kinetic energy of the molecules
the molecular size
the molecular spacing
the total number of molecules
Why do people feel cool if they do not dry themselves after swimming in the sea?
Water evaporates and causes cooling
Water insulates them from the warm air
Water is a good conductor of heat.
Water is colder than the air
At which temperature, and where in a liquid, does evaporation occur?
A
B
C
D
The rate at which thermal (heat) energy is conducted through a substance depends on its state. What is the order of conduction?
best >>>>> worst
gas > liquid > solid
liquid > gas > solid
solid > gas > liquid
solid > liquid > gas
Which line in the table describes the movement of particles in copper and in air at 20 °C?
A
B
C
D
A swimmer comes out of the water on a win day. He may feel colder before he dries himself than afterwards. Why is this?
The water is cooled down by the swimmer.
The water on his skin is colder than the air.
The water prevents warm air reaching his skin.
The wind evaporates the water, cooling his skin.
A swimmer climbs out of a swimming pool on a warm, dry day. Almost immediately he begins to feel cold. Why is this?
The water allows a convection current to remove heat from his skin.
The water takes latent heat from his body in order to evaporate.
The water on his skin is a good conductor of heat.
The water prevents infra-red radiation from reaching his body.
The diagram shows a cross-section through a rainwater puddle formed in a shallow depression in a road surface. Over a period, air temperature, wind speed and wind direction remain constant. What happens to the rate of evaporation of water from the puddle?
It decreases, because the puddle gets shallower
It increases, because the puddle gets shallower
It decreases, because the surface area decreases
It increases, because the surface area decreases
