Page 41 - BASIC CONCEPTUAL OF THERMOFLUID

3.7 IDEAL GAS MODEL TO PURE SUBSTANCES.

A perfect gas is a collection of particles that:

· are in constant, random motion,

· have no intermolecular attractions (which leads to elastic collisions in which no energy is
exchanged or lost),

· are considered to be volume-less points.

BOYLE’S LAW

P1 V1 = P2 V2 = Constant

Temperature = Constant

FIGURE 3.7: Graph P µ 1/V

FIGURE 3.8: p - v Graph for constant temperature
EXAMPLE 8

A quantity of a certain perfect gas is heated at a constant temperature from an initial state of 0.22 m 3
and 325 kN/m to a final state of 170 kN/m . Calculate the final volume of the gas.
2
2
SOLUTION : EXAMPLE 8

V = 0.22 m 3 V = ? m 3
2
1
P = 325 kN/m 2 P =170 kN/m 2
2
1

P V = P V
1 1
2 2
325 (0.22)= 170 (V2 )
V2 = 0.421m 3

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