Question

What is the entropy change of a 0.349 g spoonful of water that evaporates completely on a hot plate whose temperature is slightly above the boiling point of water?

Answer 1

`\Delta S = 2.11 J/K`

Step-by-step explanation:

As we know that entropy change for phase conversion is given as

`\Delta S = (\Delta Q)/(T)`

Here we know that heat required to change the phase of the water is given as

`\Delta Q = mL`

here we have

`m = 0.349 g = 3.49* 10^(-4) kg`

L = 2250000 J/kg

now we have

`\Delta Q = (3.49 * 10^(-4))* 2250000`

`\Delta Q = 788.9 J`

also we know that temperature is approximately same as boiling temperature

so we have

`T = 373 k`

so here we have

`\Delta S = (788.9)/(373)`

`\Delta S = 2.11 J/K`