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Question
Explain, Why is it advisabile to pour cold water over burns, caused on human body, by hot solids?
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Solution
Water has the highest specific heat capacity of 4.2 Jg-1°C-1. Thus, it can extract large amount of heat energy rapidly from the site of burn and hence gives a lot of relief.
RELATED QUESTIONS
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?
A liquid X has the maximum specific heat capacity and is used as a coolant in Car Radiators. Name the liquid X.
Two metallic blocks P and Q of masses in ratio 2: 1 are given the same amount of heat. If their temperature rise by the same amount, compare their specific heat capacities.
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.
Without green house effect, the average temperature of earth’s surface would have been:
(a) – 18℃
(b) 33℃
(c) 0℃
(d) 15℃
Why is specific heat capacity taken as a measure of thermal inertia?
Some heat is provided to a body to raise its temperature by 25°C. What will be the corresponding rise in temperature of the body as shown on the Kelvin scale?
Water falls from a height of 50 m. Calculate the rise in the temperature of water when it strikes the bottom.
(g = 10 ms-2; Specific heat capacity of water = 4200 J / kg°C)
Numerical Problem.
What could be the final temperature of a mixture of 100 g of water at 90 °C and 600g of water at 20°C.
A monoatomic gas of pressure 'P' having volume 'V' expands isothermally to a volume '2V' and then adiabatically to a volume '16V'. The final pressure of the gas is ______.
(ratio of specific heats = `5/3`)
