Question

An ideal gaseous reaction occurs at a constant pressure of 35.0 atm and releases 66.8 kJ of heat. Before the reaction, the volume of the system was 8.20 L. After the reaction, the volume of the system was 2.21 L. Calculate the total change in internal energy for the system. Enter your answer numerically in units of kJ.

Answer 1

U = -45.557kj

Explanation:

Before we can calculate the totally internal energy change in kilojoules firstly we need to calculate W

U=q + w .

We know that

w = PΔ V

where P is the pressure of

and V is the volume

then we can calculate the work

w = 35 atm * ( 8.20L - 2.21L)

W=35atm* 5.99L

W=209.65atmJ

But 1 atm = 101.325J

then ,

w = 209.65* 101.325 J = 21242.79 J

let us convert it to Kj

But we know that 1kJ = 10^3 J .

Then w = 21.243 kJ .

Then we can now calculate the internal energy as

U = 21.243- 66.8 kJ = -45.557kj

But we know that heat was released. Theeefore, the total internal energy change was -45.557kj