Isochoric change of state  means that the pressure increases, while the volume is constant.
q   : The quantity of heat ( j )
m  : mass ( Kg )
T   : Absolute temperature (K)
cv  : the heat capacity at constant
        volume (J /kg x K )
p1 : 1013.25 hPa
cv  : pdf
q = m x cv x (T2 - T1)

p2 = (p1 x T2) / T1

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m kg    Cv  J/Kg x K    T1  °K    T2  °K

p1  hPa
   q =   j         p2  hPa