Answer
$-41C^{\circ}$
Work Step by Step
We can calculate the number of moles of $C_3H_8$
as
$n=5.65g\times\frac{1 mol C_3H_8}{44.09gC_3H_8}=0.12814mol $
We know that
$PV=nRT$
$\implies T=\frac{PV}{nR}$
We plug in the known values to obtain:
$T=\frac{\frac{741}{760}\times 2.50}{0.12814\times 0.08206}=231.79K$
$T=231.79-273=-41C^{\circ}$
