Question

Determine which of the following sets of data satisfy the first law of thermodynamics? (Recall that E = total energy = U + KE + PE). a. W = 50 kJ Q = 170 kJ DeltaE = 120 kJ b. W = 100 Btu Q = -110 Btu DeltaE = -210 Btu c. W = 250 kJ Q = -110 kJ DeltaE = -100 Wh d. W = 44 kPa-m3 Q = -84 kPa-m3 DelatE = 40 kN-m

Answer 1

Answer:

Only option a and b follows the first law of thermodynamics.

Explanation:

As we know that the first law of  thermodynamics tells the conservation of energy,that is why it is also called quantitative law.

From the first law of thermodynamics

Q = ΔE + W

a.

Given that

W= 50 KJ,Q= 170KJ ,ΔE=120 KJ

Yes this follows the first law of  thermodynamics.

b.

Given that

W= 100 Btu,Q= -110 Btu ,ΔE= -210 Btu

This also satisfy the  first law of  thermodynamics.

c.

Given that

W= 250 KJ,Q= -110 KJ ,ΔE=-100 KJ

Yes this does not follow the first law of  thermodynamics.

d.

Given that

$W= 44 \frac{KPa}{m^3},Q= -84\frac{KPa}{m^3} ,\Delta E=40 \frac{KPa}{m^3}$

Yes this does not follow the first law of  thermodynamics.

So only option a and b follows the first law of thermodynamics.