Answer:
1.8 J/g·°C (2 sig.figs. per ΔT)
Explanation:
Given:
mass (m) = 78.9 grams
specific heat (c) = ?
Temp. Change (ΔT) = 109°C - 18°C = 91°C
Heat flow (q) = 13,240 Joules
q = m·c·ΔT => c = q/m·ΔT
∴c = 13,240J / 78.9g·91°C = 1.844 J/g·°C ≅ 1.8 J/g·°C (2 sig.figs. per ΔT)