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प्रश्न
How much heat energy is released when 5 g of water at 20° C changes to ice at 0° C?
[Specific heat capacity of water = 4.2 J g-1 ° C-1 Specific latent heat of fusion of ice = 336 J g-1]
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उत्तर
θ = mc Δ θ + mL
= 5 × 4.2 × 20 + 5 × 336
= 420 + 1680
= 2100 joule
संबंधित प्रश्न
Given below are observations on molar specific heats at room temperature of some common gases.
| Gas |
Molar specific heat (Cv) (cal mol–1 K–1) |
| Hydrogen | 4.87 |
| Nitrogen | 4.97 |
| Oxygen | 5.02 |
| Nitric oxide | 4.99 |
| Carbon monoxide | 5.01 |
| Chlorine | 6.17 |
The measured molar specific heats of these gases are markedly different from those for monatomic gases. Typically, molar specific heat of a monatomic gas is 2.92 cal/mol K. Explain this difference. What can you infer from the somewhat larger (than the rest) value for chlorine?
What is meant by specific heat capacity?
Study the following procedure and answer the questions below:
1. Take 3 spheres of iron, copper and lead of equal mass.
2. Put all the 3 spheres in boiling water in a beaker for some time.
3. Take 3 spheres out of the water. Put them immediately on a thick slab of wax.
4. Note, the depth that each sphere goes into the wax.
i) Which property of substance can be studied with this procedure?
ii) Describe that property in minimum words.
iii) Explain the rule of heat exchange with this property.
Explain, why is water sprayed on roads in evening in hot summer?
Explain, why temperature in hot summer, falls sharply after a sharp shower?
Write an expression for the heat energy liberated by a hot body.
Define specific heat capacity.
The specific heat capacity of ______ is maximum.
