Question

what is the change in internal energy for a system that does 70 j of work as it absorbs 45 J of heat ​

Answer 1

Answer:

–25 J

Explanation:

Given:-

q = -45J

W = 70J

According to First Law of Thermodynamics,

⇒ Internal energy (ΔU)= q+W = (-45)+70 = -25 J.

Answer 2

Answer:

The changes in internal energy for a system are -25 Joules.

Explanation:

We will use the first law of thermodynamics to solve this question. Which is given as,

$\mathrm{Q=\Delta U+w}$      (1)

Where,

Q=heat supplied to the system

ΔU=change in internal energy

w= work done by or on the system

From the question we have,

The work done by the system(w)= 70 Joules

The heat absorbed by the system(Q)=45 Joules

By substituting the value of "w" and "Q" in equation (1) we get;

$\mathrm{45=\Delta U+70}$

$\mathrm{\Delta U=45-70}$

$\mathrm{\Delta U=-25\ Joules}$

So, the change in internal energy for a system are -25 Joules.

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