Question

Calculate the amount of energy an ice maker extracts from 2200g of water at 34°C to manufacture ice at 0°C​

Answer 1

Given:

2200 g of water at 34°C.

To find:

Energy extracted to produce ice at 0°C.

Calculation:

In 1st step, water is taken to 0°C.

$\rm \: H1 = m \times c \times \Delta \theta$

$\rm \implies\: H1 = 2200 \times 1\times (0 - 34)$

$\rm \implies\: H1 = 2200 \times 1\times ( - 34)$

$\rm \implies\: H1 = - 74800 \: cal$

$\rm \implies\: H1 = - 74.8 \: kcal$

"-" (negative) sign indicates extraction of heat.

Now, latent heat of ice has to be extracted to produce ice at 0°C.

$\rm \: H2 = - m \times L$

$\rm \implies\: H2 = - 2200 \times 80$

$\rm \implies\: H2 = - 176\: kcal$

So, total heat extracted is:

$\rm \implies\: H = 176 + 74.8$

$\rm \implies\: H = 250.8 \: kcal$

So, total heat extracted is 250.8 KCal.