Question

SEP Interpret Data Look at the diagram. Imagine the following scenario: A factory where rock salt is kept in its liquid state loses power. The vat that contains the liquid rock salt begins to cool. The factory manager measures the temperature after 1 hour and again after 3 hours. Both readings show that the temperature of the salt is 801°C. What would you expect to see in the vat after 2 hours? Explain why you would expect to see this. Hint: Why would the temperature remain the same for 2 hours?

Answer 1

Heat transfer is a dynamic process in which heat is transferred spontaneously from one body to 

another cooler body.

For heat transfer:

$\text{ rate of heat transfer} =$ $\dfrac{\text{temperature difference}}{\text{over heat flow resistance of medium}}$

During processing, temperatures may change and therefore the rate of heat transfer will change in a process called unsteady-state heat transfer, contrary to steady-state heat transfer when the temperatures do not change.

Due to thermal conductivity, the temperature remains steady at $801°C$ for the two hours. The thermal conductivity of the water of effervescence in salt remains fairly constant.