How much heat transfer (in kilocalories) is required to thaw a 0.450-kg package of frozen vegetables originally at 0ºc if their heat of fusion is the same as that of water?

Question

Physics

Ryleigh Collier

20 March, 19:49

How much heat transfer (in kilocalories) is required to thaw a 0.450-kg package of frozen vegetables originally at 0ºc if their heat of fusion is the same as that of water?

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Newt · Answer 1

To thaw a product requires it to undergo the process of being subjected to latent heat of fusion. In this process, there is no change in temperature however there is a change of phase from solid to liquid. What is being thawed here actually is the frozen ice into liquid water which is in the vegetables.

From the references, the latent heat of fusion of water is:

Δ H = 333.55 kJ / kg

Therefore the amount of heat required to thaw the frozen vegetable is:

Heat required = Δ H * m

Heat required = (333.55 kJ / kg) (0.450 kg)

Heat required = 150.10 kJ

In 1 kcal there is 4.184 kJ, therefore:

Heat required = 150.10 kJ (1 kcal / 4.184 kJ)

Heat required = 35.87 kcal