#### Heat Capacities: Example Problems

Try to solve these problems before watching the solutions in the screencasts.

##### Example Problem 1

A mixture of 70.% benzene and 30.% toluene at 150°C and a flow rate of 540 mol/h is fed to a furnace. What is the outlet temperature if 22 MJ/h are added to the mixture? The heat capacity coefficients, which can be used from 273 to 1500 K are in the table.

 Molecule $$A$$ $$B x 10^2$$ $$C x 10^5$$ $$D x 10^9$$ Benzene -36.193 48.444 -31.548 77.753 Toluene -34.364 88.887 -34.435 80.335

$$C_P = A + BT + CT^2 +DT^3$$

where $$C_P$$ is in J/mol K and $$T$$ is in kelvin.

##### Example Problem 2

An ammonia stream with a flow rate of 100 mol/min is heated from 375 to 750 K. How much heat must be added per min to this stream? Use the temperature-dependent heat capacity
CP,i = Ai + BiT + CiT2
which is applicable from 300 to 1500 K. The constants are below.

 A B C 23.619 3.75E-02 1.38E-06