From dU = TdS - PdV, you know dS = dU/T - (P/T) dV
You know dU = nCvdT P/T = nR/V
ΔS = Int (nCV/T)dT - Int(nR/V)dV = nCvln(T2/T1) - nRln(V2/V1)
You can plug into this. Make sure that T's are in Kelvin and R = 8.314 J/mole-K
V2/V1 = T2/T1 * P1/P2 (any units are ok as long as physical quantities for two states are in the same units.
Please consider a tutor. Take care.