Question

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?

Answer 1

m_w = mass of whisky = 55 g = 0.055 kg

T_wi = initial temperature of whisky = 22 ^∘C

m_s = mass of stones = 3 x 32 g = 96 g = 0.096 kg

T_si = initial temperature of stones = - 11 ^∘C

c_s = specific heat of stone = 980 J/kgK

c_w = specific heat of whisky= 3400 J/kgK

T = final equilibrium temperature

using conservation of heat

Heat lost by whisky = heat gained by stones

m_w c_w (T_wi - T) = m_s c_s (T - T_si )

inserting the values

(0.055) (3400) (22 - T) = (0.096) (980) (T - (-11) )

T = 11 ^∘C