Infer a gas model from its energy split

A gas receives 700 J during reversible constant-pressure heating and does 200 J of boundary work. Its active modes and composition stay fixed.

What is its ratio γ = Cp/Cv?

Organize the givens & assumptions

Q = 700 J
W = 200 J
Constant pressure

Closed fixed amount of ideal gas, constant stated heat capacities, negligible bulk kinetic and gravitational energy changes, and only pressure–volume work. Heat into the gas and work by the gas are positive.

A $0.4$
B $1.4$
C $3.5$
D $2.5$

Try it on paper first. Free sample problems in every collection include the complete reasoning: find one in this collection →