alleryStart learning →How much heat is needed to vaporize 1.000 kg of water already at 100 degrees Celsius? Use the latent heat of vaporization of water, 2256 kJ/kg.
A1128 kJ
B2256 kJ
C3384 kJ
D4512 kJ
Answer & Solution
Correct answer: B. 2256 kJ
1. Vaporizing a liquid uses the relationship Q = mLv, where Lv is the latent heat of vaporization.
2. Substitute m = 1.000 kg and Lv = 2256 kJ/kg.
3. Multiply: Q = 1.000 x 2256 = 2256 kJ.
4. 1128 kJ is half the correct value, while 3384 kJ and 4512 kJ are one and a half and two times too large.
5. So 2256 kJ is correct.
_Source: OpenStax Physics (CC BY 4.0), Ch 11 "Thermal Energy, Heat, and Work", section 11.3 Phase Change and Latent Heat_
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