# Homework Help: Thermodynamics Isochoric process .

1. May 26, 2013

### manal950

Hi

A certain Gas of volume 0.4 m3, pressure of 4.5 bar
and temperature of 1300 C is heated to in a cylinder to 9 bar when the volume remains
constant. Calculate

¨ (i) Temperature at the
end of the process,

¨ (ii) the heat transferred

¨(iii) change in internal energy

¨ (iv) work done

¨(v) change in enthalpy.

¨Assume Cp = 1.005 kJ/kg.K and Cv=
0.71005 kJ/kg.K

p1v1=mRT

4.5 X 100 X 0.4 = m X 0.28 X 403

m= 1595 kg

now
i) p2v2 = mRT
9 X 100 X 0.4 = 1.1595 X 0.28 X T
T = 806 K

ii ) the heat transferred
no heat transferred because the work = 0

(iii) change in internal energy

Cv(T2 - T1 )
0.71005(806 - 40)
= 54.86

(iv) work done = 0

(v) change in enthalpy.
Cp (T2 - T1 )
1.005(806 - 40)
=769.83

2. May 28, 2013

### Staff: Mentor

I'll stop you here: what are you doing?

3. May 28, 2013

### SteamKing

Staff Emeritus
According to you, it is impossible for a stove to heat up a tea kettle because no work is done by the stove.

Also the OP says the initial temp. is 1300 C, rather than 130 C.