Acylinder with a movable piston contains 20.5 moles of a monatomic ideal gas at a pressure of 2.86 × 105 pa. the gas is initially at a temperature of 300 k. an electric heater adds 58600 j of energy into the gas while the piston moves in such a way that the pressure remains constant. it may you to recall that cp = 20.79 j/k/mole for a monatomic ideal gas, and that the number of gas molecules is equal to avagadros number (6.022 × 1023) times the number of moles of the gas. what is the temperature of the gas after the energy is added?

437.49 K

Explanation:

Given:

The number of moles, n = 20.5 moles

Initial pressure P₁ = 2.86 × 10⁵ Pa

Initial temprature, T₁ = 300 K

Cp = 20.79 J/K/mole

Now

the Initial volume V₁ is given as

V₁ =

where, R is the gas constant

substituting the value in the above equation, we get

V₁ =  

or

V₁ =0.178 m³

the energy added (Q) =58600 J

also, we know that

Q = nCp(T ' - T )

where, T₂ is the final temperature

substituting the values in the equation, we get

58600 = 20.5 × 20.79 × (T ' - 300 )

T₂ - 300 = 137.49

or

T₂ = 437.49 K

option number c is the right answer.

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