Q3.
q = mCΔT
C = q/(mΔT) = 1444 J/(250.0 g × 15.0 °C) = 0.385 J.°C^(-1)g^(-1)
Q4.
ΔT = (75.0 – 22.0) °C = 53.0 °C
C = 4.184 J.°C^(-1)g^(-1)
m = q/(CΔT) = 1200 J/[4.184 J.°C^(-1)g^(-1) × 53.0 °C] = 5.41 g
