A chemist heats a 215-g sample of iron from 25°C to 90°C. How much heat (q) did the iron absorb? The specific heat capacity of iron is 0.45 J/g°C. Use q = mcΔT
Solution:
q = m × C × ΔT
q = m × C × (Tf - Ti),
where:
q = amount of heat energy gained or lost by substance (J)
m = mass of sample (g)
C = specific heat capacity (J °C-1 g-1)
Tf = final temperature (°C)
Ti = initial temperature (°C)
Thus:
q = (215 g) × (0.45 J oC-1 g-1) × (90 - 25)°C = 6288.75 J
q = 6288.75 J = 6.3 kJ
Answer: the iron absorb 6.3 kJ of heat (q).
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