Answer: 418 J
Step-by-step explanation:
The equation for working out the amount of thermal energy required is q = m c Δ T , where q is the amount of energy, m is the mass being heated up in grams, c is the specific heat capacity of what you're heating up in joules per gram per kelvin, and Δ T is the change in temperature in Kelvin.(Change in temperature will always give the same value,no matter Celsius or Kelvin)
mass = 20g, the given specific heat capacity of water is 4.18 J/g*K, and the change in temperature is 5K , the energy needed to raise : 5 × 20 × 4.18 = 418 J .