Advertisements
Advertisements
Question
How much heat energy is released when 5.0 g of water at 20℃ changes into ice at 0℃? Take specific heat capacity of water = 4.2 J g-1 K-1, Specific latent heat of fusion of ice = 336 J g-1.
Advertisements
Solution
Given,
Mass (m) = 5.0 g
Specific heat capacity of water (c) = 4.2 J g-1 K-1
Specific latent heat of fusion of ice (L) = 336 J g-1
(i) Heat energy released when water lowers it's temperature from 20° C to 0° C
= m × c × change in temperature
Substituting the values in the formula we get,
Q1 = 5 × 4.2 × (20 − 0)
Q1 = 5 × 4.2 × 20
⇒ Q1 = 420 J
(ii) Heat energy released when water at 0° C changes into ice at 0° C = m × L
Substituting the values in the formula we get,
Q2 = 5 × 336 J
⇒ Q2 = 1680 J
From relation,
Q = Q1 + Q2
Q = 420 + 1680
Q = 2100
Total heat released = 2100 J
APPEARS IN
RELATED QUESTIONS
In an experiment on the specific heat of a metal, a 0.20 kg block of the metal at 150 °C is dropped in a copper calorimeter (of water equivalent 0.025 kg) containing 150 cm3 of water at 27 °C. The final temperature is 40 °C. Compute the specific heat of the metal. If heat losses to the surroundings are not negligible, is your answer greater or smaller than the actual value for the specific heat of the metal?
What do you mean by the following statement?
The specific heat capacity of copper is 0. 4 Jg-1 K-1?
Fill in the following blank using suitable word:
SI unit of heat is .........
The temperature of a lead piece of mass 400 g rises from 20°C to 50°C when 1560 J of heat is supplied to it. Calculate Specific heat capacity of lead.
Read this activity and answer the following questions.
- Take three spheres of iron, copper and lead. the lead of equal mass.
- Put all the three spheres in boiling water in the beaker for some time.
- Take the three spheres out of the water.
- All the spheres will be at a temperature 100 °C.
- Put them immediately on the thick slab of wax.
- Note, the depth that each of the sphere goes into the wax.
Questions:
- Which property is determined from this activity?
- Give name to that property.
- Explain the term principal of heat exchange with the help of this activity.
When a uniform rod is heated, which of the following quantity of the rod will increase
A piece of lead weighing 500 g gives out 1200 calories of heat when it is cooled from 100° C to 20° C. Find its specific heat.
Two metals A and B have specific heat capacities in the ratio 2:3. If they are supplied same amount of heat then
If specific heat capacity of metal A is 0.26 Jg-1 0C-1 then calculate the specific heat capacity of metal B.
Specific heat capacity of a substance X is 1900 Jkg-1°C-1 means ______.
Calculate the amount of heat energy required to raise the temperature of 200 g of copper from 20°C to 70°C. Specific heat capacity of copper = 390 J kg-1 K-1.
