Answer:
270 Joules
Explanation:
The specific heat capacity equation will be used for this question i.e.
Q = m. c. ΔT
Where; Q = Amount of heat
m = mass of substance
C = specific heat capacity of
substance
ΔT = change in temperature
(Final temp - initial temp)
However, for this unknown metal, we need to find the specific heat first by saying; C = Q / mΔT
Q= 135J, C=?, m= 10g, ΔT = (40-25 = 15°C)
C = 135 / 15 × 10
C = 135/150
C = 0.9 J/g°C
If the specific heat capacity of the unknown metal is 0.9 J/g°C, then at a mass of 20.0g, and a ΔT of 15°C, the amount of heat needed is:
Q = m. c. ΔT
Q = 20 × 0.9 × (40-25)
Q = 18 × 15
Q = 270J
270 Joules of heat is needed to increase the temperature of 20g of the metal from 25 - 40°C
