# Latent Heat

## Trending Questions

**Q.**

50 g of ice at 0 °C is added to 300 g of a liquid at 30 °C. What will be the final temperature of the mixture when all the ice has melted? The specific heat capacity of the liquid is 2.65 J g^{-1} °C^{-1} while that of water is 4.2 J g^{-1o}C^{-1} and Specific latent heat of fusion of ice = 336 J g^{-1}

10.7°C

12.2 °C

7.01°C

9.2°C

**Q.**

Calculate the amount of heat required to convert 1.00 kg of ice at -10°C

at normal pressure to steam at 100°C.

The specific heat capacity of ice=2100 Jkg−1K−1

Latent heat of fusion of ice=3.36×105 Jkg−1

The specific heat capacity of water=4200 Jkg−1K−1

Latent heat of vaporization of water=2.25×106 Jkg−1

**Q.**

10 g of ice at 0oC absorbs 5460 J of heat energy to melt and change to water at 50oC. Calculate the specific latent heat of fusion of ice. Specific heat capacity of water is 4200 J kg−1 K−1.

**Q.**

The amount of heat energy required to convert 1 kg of ice at −10∘C to water at 100∘C is 7, 77, 000 J. Calculate the specific latent heat of ice.

Specific heat capacity of ice = 2100 J kg−1 K−1, specific heat capacity of water=4200 J kg−1 K−1.

**Q.**When you pour spirit onto your palm, you feel a cold sensation. This is because of the fact that

- spirit has cooler molecules
- our skin is very hot when compared to the spirit
- spirit is cooler than air
- spirit absorbs heat from ones hand's surface and changes its state.

**Q.**

The unit of latent heat is ______

**Q.**

Which has more heat: 1 g of ice at 0o C or 1 g of water at 0o C ? Give reason.

**Q.**What is the difference between latent heat and specific latent heat ?

**Q.**

How does the (a) average kinetic energy (b) average potential energy of molecules of a substance change during its change in phase at a constant temperature, on heating ?

**Q.**

Steam at 100oC is passed into 1.1 kg of water contained in a calorimeter of water equivalent 0.02 kg at 15oC till the temperature of the calorimeter and its contents rises to 80oC. The mass of the steam condensed in kg is

0.130

0.065

0.135

0.260

**Q.**

A refrigerator converts 100 g of water at 20o C to ice at −10o C in 73.5 min. Calculate the average rate of heat extraction in watt. The specific heat capacity of water is 4.2 J g−1K−1, specific latent heat of ice is 336 J g−1 and the specific heat capacity of ice is 2.1 J g−1 K−1.

**Q.**

Why does ice at 0^{0}C have a better cooling effect than water at 0^{0}C?

As ice absorbs extra amount of heat equivalent to latent heat of fusion which water already possesses

As ice has a greater SHC as compared to water

As water absorbs extra amount of heat equivalent to latent heat of fusion which ice already possesses

As ice absorbs heat on cooling but water liberates heat on cooling due to anomalous behaviour of water

As ice has a larger volume than water of the same mass

**Q.**

Ice cream appears colder to the mouth than water at 0oC. Give reason.

**Q.**

2 kg of ice melts when water at 100∘ is poured in a hole drilled in a block of ice. What mass of water was used?

Given: Specific heat capacity of water=4200 J kg−1 K−1, specific latent heat of ice=336×103 J kg−1.

**Q.**

200 g of ice at 0∘C convert into water at 0∘C in 1 minute when heat is supplied to it at a constant rate.In how much time 200 g of water at 0∘C will change to 20∘C?Take specific latent heat of ice =336 ) J g−1.

**Q.**

The soft drink bottles are cooled by (i) ice cubes at 0oC, and (ii) Iced-water at 0oC. Which will cool the drink quickly ? Give reason.

**Q.**

Pieces of ice added to a drink cool it much faster than ice cold water added to it because

Ice pieces at 0°C possess latent heat of fusion, whereas water at 0°C does not possess latent heat of fusion

Ice pieces at 0 °C possess heat capacity, whereas water at 0 °C does not possess latent heat of fusion

Ice pieces at 0°C do not possess heat capacity, whereas water at 0°C does not possess latent heat of fusion

Ice pieces at 0°C do not possess latent heat of fusion, whereas water at 0°C possess latent heat of fusion

**Q.**

In a laboratory experiment for finding specific latent heat of ice, 100 g of water at 30^{o}C was taken in a calorimeter made of copper and of mass 10 g. When 10 g of ice at 0^{o}C was added to the mixture and kept within the liquid till the ice melted completely, the final temperature of the mixture was found to be 20^{o}C.

Calculate the value of the latent heat of fusion of ice from the data discussed above.

320 Jg

^{-1}336 Jg

^{-1}400 Jg

^{-1}340 Jg

^{-1}

**Q.**

Find the result of mixing 10 g of ice at -10∘C with 10 g of water at 10∘C.Specific heat capacity of ice=2.1 J g−1 K−1, specific latent heat of ice=336 J g−1 and specifc heat capacity of water =4.2 J g−1 K−1.

**Q.**

While constructing a house in a coastal area, in which direction should the windows preferably face and why?

**Q.**

When the heat supplied causes no change in the temperature of the substance, the heat supplied to the substance is utilised to

Change the Kinetic Energy of the molecules

Change the state by breaking bonds

Change the state by overcoming intermolecular forces of attractions

Change the shape and size of the molecules

**Q.**

Which of the following has the Highest Specific Heat:

Water

Copper

Mercury

Kerosene

**Q.**

A substance on heating, undergoes (i) a rise in its temperature, (ii) a change in its phase without change in its temperature. In each case, state the change in energy of molecules of the substance.

**Q.**

The specific latent heat of fusion of water is:

(a) 80 cal g−1

(b) 2260 J g−1

(c) 80 J g−1

(d) 336 J kg−1

**Q.**What is the specific latent heat of fusion of water in SI and CGS units

**Q.**

A molten metal of mass 150 g is kept at its melting point 800oC. When it is allowed to freeze at the same temperature, it gives out 75, 000 J of heat energy.

(a) What is the specific latent heat of the metal ?

(b) If the specific heat capacity of metal is 200 J kg−1 K−1, how much additional heat energy will the metal give out in cooling to −50o C ?

**Q.**

1300 J of heat energy is supplied to raise the temperature of 0.5 kg of lead from 200C to 400C. Calculate the specific heat capacity of lead.

150

130

200

100

**Q.**In cold regions in winter, the rocks crack due to anomalous expansion of water.

**Q.**

A solid metal weighing 150g melts at its melting point of ${800}^{o}C$ by providing heat at the rate of 100W. The time taken for it to completely melt at the same temperature is 4min. What is the specific latent heat of fusion of the metal?

**Q.**

The S.I. unit of specific latent heat is :

(a) cal g−1

(b) cal g−1K−1

(c) J kg−1

(d) J kg−1 K−1