Advertisements
Advertisements
Question
A molten metal of mass 150 g is kept at its melting point 800℃. When it is allowed to freeze at the same temperature, it gives out 75,000 J of heat energy.
- What is the specific latent heat of the metal?
- 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 -50℃?
Solution
- Mass of metal = 150 g
Specific latent heat of metal
L = `"Q"/"m"`
= `75000 / 150`
= 500 J g-1 - Specific heat capacity of metal is 200 J kg-1K-1.
Change in temperature= 800 − (−50)
= 850°C (or 850 K).
ΔQ = mcΔT
= 0.15 × 200 × 850
= 25500 J
APPEARS IN
RELATED QUESTIONS
What is the Greenhouse effect?
What is the energy absorbed during the phase change called?
What do you understand by the term latent heat?
1 g ice of 0℃ melts to form 1 g water at 0℃. State whether the latent heat is absorbed or given out by ice.
Calculate the total amount of heat energy required to convert 100 g of ice at −10℃ completely into water at 100℃. Specific heat capacity of ice = 2.1 J g-1 K-1, specific heat capacity of water = 4.2 J g-1K-1, specific latent heat of ice = 336 J g-1.
Explain why water is used in hot water bottles for fomentation and also as a universal coolant.
Why does evaporation causes cooling and why is water used in hot water bottles?
Explain the meaning of greenhouse effect.
State the main precautions to be taken in finding the latent heat of steam.
What observation you will record and how will you determine the specific latent heat of fusion of ice?
If there is no Heat loss to the surroundings, the heat released by the condensation of m1 g of steam at 100°C into water at 100°C can be used to convert m2 g of ice at 0°C into water at 0°C.
(i) Find:
(a) The heat lost by steam in terms of m1
(b) The heat gained by ice in terms of m2
(ii) Form a heat equation find the ratio of m2 : m1
Specific latent heat of vaporization of steam = 2268 kJ/kg
Specific latent heat of fusion of ice = 336 kJ/kg
Specific heat capacity of water = 4200 J/kg°C
If pressure increases, the melting point of a substance ______.
Find the odd one out and give its explanation.
Match the columns.
| Column A | Column B |
| 1) Absolute humidity | a) J or cal |
| 2) Latent heat | b) J/kg °C |
| 3) Specific heat capacity | c) kJ/kg |
| 4) Heat | d) no unit |
| e) kg/m3 |
The latent heat of vaporisation is a term referred for the conversion of gas into liquid.
Write scientific reason.
Use a pressure cooker to cook food in cold air.
600 g of copper at 50°C is mixed with lOOOg water at 20°C. Find the final temperature of the mixture. The specific heat capacity of copper is 0.4 Jg-1°C-1 and that of water is 4.2 Jg-1°C-1
