Question

a cylinder of volume 0.240 m^3 contains 10.3 mol of neon gas at 19.0 C. assume neon behaves as an idea gas.

a) what is the pressure of the gas

b) find the internal energy of the gas

c) suppose the gas expands at a constant pressure to a colume of 1.000m^3. how much work is done on the gas?

d) what is the temperature of the gas at the new volume

e) find the internal energy of the gas when its volume is 1.000m^3.

f) compute the change in the internal energy during the expansion

h) must thermal energy be transferred to the gas during the constant pressure expansion or be taken away?

i) compute Q, the thermal energy transfer

Answer 1

given
V1 = 0.240 m^3
n = 10.3 mol
T1 = 19 C = 19 + 273 = 292 K

a) use, P1*V1 = n*R*T1

P1 = n*R*T1/V1

= 10.3*8.314*292/0.24

= 1.042*10^5 pa <<<<<<<--------------Answer

b) internal energy, U1 = (3/2)*n*R*T1

= (3/2)*10.3*8.314*292

= 3.75*10^4 J <<<<<<<<<<------------Answer

c) Workdone by the gas, W = P1*(V2 - V1)

= 1.042*10^5*(1 - 0.24)

= 7.92*10^4 J <<<<<<<<----------------Answer

d) at constant pressure, V/T = constant

so, V1/T1 = V2/T2

T2 = T1*(V2/V1)

= 292*(1/0.24)

= 1217 K (or) 944 C <<<<<<<<-------------Answer

e) U2 = (3/2)*n*R*T2

= (3/2)*10.3*8.314*1217

= 1.56*10^5 J <<<<<<<<<---------------Answer

f) delta_U = U2 - U1

= 1.56*10^5 - 7.92*10^4

= 7.68*10^4 J <<<<<<<---------Answer

h) thermal energy must be transferred to the gas during the constant pressure expansion.

i) Q = delta_U + W

= 7.68*10^4 + 7.92*10^4

= 1.56*10^5 J <<<<<<<<<------------Answer