A bar of pure gold is heated to 95.0 degrees Celsius. The specific heat capacity of gold is 1.29 X 10^2. The gold is placed into 500 mL of ethyl alcohol initially at a temperature of 25 Celsius. The final temperature of the mixture is 27.0 Celsius. What is the mass of the gold?

First we have to use conservation of energy, that the heat transferred from gold to the alcohol used to raise the temperature of the alcohol by 2 degrees.

the heat lost by gold = heat required by the methyl

(m of gold) (C of gold) (dTof gold) = (m of ethyl) (C of ethyl) (dT of ethyl)

where;

m of gold is the unknown to be determined

c of gold is the specific heat of gold

dT of gold is the change in temperature in gold

m of ethyl is the mass of ethyl alcohol

C of ethyl is the specific heat of ethyl

dT is the change in temperature in ethyl alcohol

now

mass of gold = unknown

c of gold = 129

dT of gold = 95 - 25 = 68 degrees

m of ethyl = density of ethyl * volume of ethyl

789 X 0.5 X 10^ (-3) = 0.3945

mass of gold = 0.3945 kg