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प्रश्न
Water boils at 120 °C in a pressure cooker. Explain the reason.
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उत्तर
- The boiling point of a liquid rises with increased pressure and falls with decreased pressure. At one atmosphere pressure, pure water has a boiling point of 100°C.
- A pressure cooker does not allow steam to escape. Because of the increased pressure, the vapor pressure on the water inside the cooker rises to approximately 1.75 times that of the atmosphere, causing water to boil at around 120°C to 125°C.
संबंधित प्रश्न
Heat energy is supplied at a constant rate to 100g of ice at 0 °C. The ice is converted into water at 0° C in 2 minutes. How much time will be required to raise the temperature of water from 0 °C to 20 °C? [Given: sp. heat capacity of water = 4.2 J g-1 °C-1, sp. latent heat of ice = 336 J g-1].
104g of water at 30°C is taken in a calorimeter made of copper of mass 42 g. When a certain mass of ice at 0°C is added to it, the final steady temperature of the mixture after the ice has melted, was found to be 10°C. Find the mass of ice added. [Specific heat capacity of water = 4.2 Jg–1°C–1 ; Specific latent heat of fusion of ice = 336 Jg–1; Specific heat capacity of copper = 0.4 Jg–1°C–1] .
(b) 2000 J of heat energy is required to raise the temperature of 4 kg of a
metal by 3°c. Which expression gives the specific heat capacity of the metal?
The farmers fill their fields with water in winter. Give reason.
Calculate the ratio of two specific heats of polyatomic gas molecules.
For a gas, `"R"/"C"_"v"=0.4`, where R Is universal gas constant and Cv is the molar specific heat at constant volume. The gas is made up of molecules, which are ______
50 g of copper is heated to increase its temperature by 10° C. If the same quantity of heat is given to 5 g water, the rise in its temperature is [Specific heat of copper = 420 joule-kg-1 °C-1 , specific heat of water = 4200 joule-kg-I °C-1]
The specific heat capacity of water is ______.
Match the following:
| Column A | Column B | ||
| 1. | Specific heat capacity of water | a. | 0°C |
| 2. | Latent heat of fusion of ice | b. | 2260 J/g |
| 3. | Latent heat of vaporization of water | c. | 100°C |
| 4. | The melting point of iced | d. | 4.2 J/g°C |
| 5. | The boiling point of water | e. | 336 J/g |
