Calculate the change in enthalpy

1. Nov 5, 2005

asdf1

how do you solve the following problem?

calculate the change in enthalpy and the change in entropy when 1 mole of SiC is heated from 25 degrees C to 1000 degrees C.
Cp=50.79+1.97*(10^-3)T-4.92*(10^6)(T^-2)+8.2*(10^8)(T^-3) J/(mole*K)

2. Nov 5, 2005

siddharth

The variation of Entropy with temperature for a system is given by
$$S(T_f) = S(T_i) + \int \frac{dq_{rev}}{T}$$
When the system is under constant pressure and there is no non-expansion work,
$$dq_{rev} = C_p dT$$

3. Nov 6, 2005

asdf1

how do you know that the question is under constant pressure?

4. Nov 6, 2005

because they give u Cp, which is the specific heat at constant pressure

5. Nov 6, 2005

asdf1

@@
how do you know that there's no non-expansion?

6. Nov 6, 2005

siddharth

Non expansion work is work done by the system other than in expansion.
For example, electrical work. So unless it is specifically stated, there is usually no non-expansion work.

7. Nov 6, 2005

asdf1

thank you very much!!!