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Const@ntine

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## Homework Statement

A cylinder with a heavy ram/piston contains air at T = 300 K. Pi = 2.00 * 10

^{5}Pa, Vi = 0.350 m

^{3}, Mr = 28.9 g/mol & Cv = 5R/2

(a) What's the Molecular Specific Heat of an Ideal Gas, with a constant volume, computed at J/KgC ? (Cv)

(b) What's the mass of the air inside the cylinder?

(c) If the piston stands still, how much energy is required for Tf = 700 K?

(d) If the piston is free to move, how much energy is required for Tf = 700 K?

## Homework Equations

ΔE = nCvΔT

PV = nRT

Cv = R + Cp

## The Attempt at a Solution

(a) No clue what to do here.

(b) PiVi = nRTi <=> ... <=> n = 28.065 mol = m/Mr = m/28.9(g/mol) <=> ... <=> m = 0.811 kg

(c) ΔE = nCvΔT = 28.065 mol * (5/2 * 8,314 J/molK) * (700 - 300) K <=> ΔE = 233 kJ

(d) No clue what to do here either.

Any help is appreciated!