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Air(ideal gas) at 292.15k is expended by a piston from 600cm^3 to 900cm^3 at a temperature of 550k at 900kpa pressure. find the pressure before expansion.

User Tommed
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1 Answer

4 votes

Answer:

The pressure before expansion is 717.1 kPa.

Step-by-step explanation:

We need to use the Ideal Gas equation to find the initial pressure:


PV = nRT

Where:

P: is the pressure

V: is the volume

n: is the number of moles

R: is the gas constant

T: is the temperature

Since the number of moles does not change after the expansion, we need the following number of moles:


n = (P_(f)V_(f))/(RT_(f)) (1)

Where "f" is for final

Before the expansion, the pressure is:


P_(i) = (nRT_(i))/(V_(i)) (2)

By entering equation (1) into (2) we have:


P_(i) = ((P_(f)V_(f))/(RT_(f)))((RT_(i))/(V_(i)))


P_(i) = (P_(f)V_(f)T_(i))/(T_(f)V_(i)) = (900 kPa*900 cm^(3)*292.15 K)/(550 K*600 cm^(3)) = 717.1 kPa

Therefore, the pressure before expansion is 717.1 kPa.

I hope it helps you!

User Redolent
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