alleryStart learning →How much energy is needed to melt 2.00 kg of ice already at 0 degrees Celsius? Use Lf(water) = 334 kJ/kg.
A167 kJ
B334 kJ
C501 kJ
D668 kJ
Answer & Solution
Correct answer: D. 668 kJ
1. Apply Q = mLf with m = 2.00 kg and Lf = 334 kJ/kg.
2. Multiply: Q = 2.00 x 334 = 668 kJ.
3. 334 kJ is the amount needed for only half this mass, 1.00 kg.
4. 167 kJ and 501 kJ do not match doubling 334 kJ at all.
5. So 668 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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