The heat required to convert 2 kg of water at 100°C to steam at 100°C (latent heat of vaporization = 2260 kJ/kg) is:
Correct answer: A. 4520 kJ
- A. 4520 kJ
- B. 9040 kJ
- C. 2260 kJ
- D. 4180 kJ
Explanation
For the phase change from water to steam at 100°C, only latent heat is required (no temperature change). Heat = m·Lv = 2 × 2260 = 4520 kJ.
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Thermal equilibrium means that bodies in contact have the same temperature and no net heat flows between them. The topic distinguishes heat from temperature, uses the zeroth law of thermodynamics, and covers heat transfer, specific heat capacity, thermal expansion and the conditions for reaching equilibrium.
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