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प्रश्न
Steam at 100°C is passed over 1000 g of ice at 0°C. After some time, 600 g of ice at 0°C is left and 450 g of water at 0°C is formed. Calculate the specific latent heat of vaporization of steam (Given: specific heat capacity of water = 4200 J/kg°C, specific latent heat of fusion of ice = 336,000 J/kg.)
उत्तर
Let 'L' J/kg be the specific latent heat of vaporisation of steam.
Mass of ice method = (1000 - 600)g = 400g = 0.4 kg
∴ Mass of steam condensed into water = (450 - 400) = 50g = 0.05 kg
(i) Heat given out by steam in condensing into water at the same temperature i.e., 100°C
= mL = 0.05 × L = 0.050 L J
(ii) Heat given out by 0.050 kg of water at 100°C in cooling down to 0°C
= mst = (0.50 × 4200 × 100) J = 21000 J
(iii) Heat taken up by ice in melting into water at the same temperature
= ml = 0.4 × 336000 J
Heat given out = Heat taken up
0.050 L + 21000 = 0.4 × 33600
L = `(0.4 xx 336000 - 21000)/0.050` = 2268000 J/kg
Latent heat of vaporisation of steam = 2268000 J/kg.
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संबंधित प्रश्न
State two factors upon which the rate of emission of thermions depends.
What do you understand by the term latent heat?
Write the approximate value of specific latent heat of ice.
The S.I. unit of specific latent heat is ______.
The specific latent heat of fusion of water is ______.
Answer the following:
Explain the role of latent heat in the change of state of a substance.
Water expands on reducing its temperature below ______°C.
What do you mean by the statement?
'The specific latent heat capacity of fusion of ice is 336 J per g'?
Define specific latent heat of vaporization of a substance.
The specific latent heat of vaporisation of steam is 2260 J/g. Comment on this.
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
1 kg of water is contained in a 1.25 kW kettle. Assuming specific heat capacity of water = 4.2 J/g °C and specific latent heat of vaporization = 2260 J/g, calculate:
(i) the time taken for the temperature of water to rise from 25°C to its boiling point,
(ii) the mass of water which evaporates per minute from the boiling water.
Define boiling point of a liquid.
Write scientific reason.
The bottom of some steel utensils used for cooking is copper.
2875 J of heat is required to melt 115 g of lead at its melting point. Calculate the specific latent heat capacity of fusion of lead.
Calculate the total amount of heat energy required to melt 200 g of ice at 0°C to water at 100°C. (Specific latent heat of ice = 336 Jg-1, specific heat capacity of water = 4.2 Jg-1 °C-1)
