To determine the amount of heat required to change 20 g of ice at -10℃ into water at 20℃, we need to consider two processes: heating the ice from -10℃ to its melting point, and then heating the resulting water from its melting point to 20℃. We'll calculate the heat required for each step separately and then add them together.
Heating the ice from -10℃ to its melting point: The specific heat capacity of ice is approximately 2.09 J/g°C. Since the initial temperature is -10℃ and the melting point of ice is 0℃, we need to raise the temperature by 10℃. Heat required = mass × specific heat capacity × temperature change Heat required = 20 g × 2.09 J/g°C × 10°C = 418 J
Heating the resulting water from its melting point to 20℃: The specific heat capacity of water is approximately 4.18 J/g°C. We need to raise the temperature by 20℃. Heat required = mass × specific heat capacity × temperature change Heat required = 20 g × 4.18 J/g°C × 20°C = 1,672 J
Now, we can add the heat required for each step to find the total heat required: Total heat required = heat for step 1 + heat for step 2 Total heat required = 418 J + 1,672 J = 2,090 J
Therefore, approximately 2,090 Joules of heat are necessary to change 20 g of ice at -10℃ into water at 20℃.