If you pour whisky over ice, the ice will cool the drink, but it will also dilute it. A solution is to use whisky stones. Suppose Ernest pours 55.0 g of whisky at 22 ∘C room temperature, and then adds three whisky stones to cool it. Each stone is a 32.0 g soapstone cube that is stored in the freezer at -11 ∘C. The specific heat of soapstone is 980 J/kg⋅K; the specific heat of whisky is 3400 J/kg⋅K. What is the final temperature of the whisky?

10.1 °C

Explanation:

After the mixture, heat is gained by the soapstone cubes (they were at a lower temperature) while heat is lost by the whisky (it was at a higher temperature).

Let the temperature of the mixture be T.

Heat lost by whisky,

is the mass of the whisky (in kg), is the specific heat of whisky (J/kg·K) and is the change in temperature of the whisky (in °C or K).

Heat gained by soapstone cubes,

There are three cubes of soapstone, so their mass is multiplied by 3.

From the principle of mixtures,

Heat lost by whisky = Heat gained by soapstone cubes (assuming no heat loss to the surroundings)

The final temperature of the whisky is 10.1 °C.

which statement about this sum is true? −245+2.7