Question

Consider a mixture of air and gasoline vapor in

a cylinder. The original volume is 40. cm3. If the

combustion releases 950 J of energy, to what volume

in L will the gases expand against a constant

pressure of 650 torr if all the energy of combustion is

converted into work to push back the piston?

I know how to do the problem... you just do 950 = P*deltaV, butwhat units would I use for pressure and for volume to yieldjoules?

Answer 1

11 L

Step-by-step explanation:

Work-done = P (V₂ - V₁)--------------------------------------- (1)

P= 650 torr

= 86659.5 N/m²

V₁=40 cm³

= 40 x 10⁻⁶ m³

V₂ = ?

Workdone =950 J

Substituting into equation (1)

950 = 86659.5 ( V₂- 40 x 10⁻⁶ )

V₂= (950/86659.5) + 40 x 10⁻⁶

= 0.01096 + 40 x 10⁻⁶

= 0.011 ‬m³

= 11 L