What is the specific heat of an unknown substance if 2000 J of energy are required to raise the temperature of 4 grams of the substance 5 degrees Celsius?

The energy required to heat a substance is related by the formula:

Q = mCpΔT; where Q is the energy, m is the mass of the substance, Cp is the specific heat capacity and ΔT is the change in temperature.

2000 = (4) (Cp) (5)

Cp = 100 Joules / g °C