The specific heat capacity of the given substance is -0.66 J/g°C.
Step-by-step explanation:
The heat absorbed by any substance is the product of its mass, specific heat capacity and change in temperature.
q = m × c × ΔT
m is the mass in grams
q = amount of heat released or absorbed in J
ΔT = change in temperature in °C = 5 -50 = -45°C
c = specific heat capacity in J/g°C
c =

Plugin the values, we will get,
c =

= -0.66 J/g°C