In: Physics
Suppose I pour 13.5 mL of creamer into 159 mL of hot coffee. The creamer is at 43.4 deg F, and the coffee is at 188 deg F. What is the final temperature when the system reaches equilibrium, in deg F? Assume coffee and creamer have the same density and thermal properties of water.
Let the final temperature of the system be 'T', then
according to heat balance,
the heat lost by coffee is equal to the heat gained by the creamer
Given, cpcoffee = cpcreamer = cpwater = c (say)
cp represents the specific heat
and, coffee =
creamer
=
water =
(say)
represents
density
initial temperature of coffee = 188 F = 359.817 K
initial temperature of creamer = 43.4 F = 279.483 K
heat lost by coffee, Qcoffee =
mcoffee*cpcoffee*dTcoffee =
Vcoffee**c*(359.817-T) =
159*
*c*(359.817-T)
heat lost by creamer, Qcreamer =
mcreamer*cpcreamer*dTcreamer =
Vcreamer**c*(T-279.483) =
13.5*
*c*(T- 279.483)
According to heat balance
Qcoffee = Qcreamer
159**c*(359.817-T) =
13.5*
*c*(T- 279.483)
57210.903 - 159T = 13.5T - 3773.02
T = 353.53 K
OR T = 176.683 degree F