Chapter 20 - The Second Law of Thermodynamics - Problems - Exercises - Page 677: 20.10

(a) $Q = −8.09 × 10^5 J $ (b) $|W| = 3.37 × 10^5 J $ (c) $|𝑄_𝐻| = 1.15 \times 10^6 J $

(a) Amount of heat must be removed from the water $Q = mc_{ice}ΔT_{ice} − mL_f + mc_wΔT_w$ $Q = (1.80 kg) [(2100 J/kg⋅K)(−5.0 °C) − 3.34×10^5 J/kg + (4190 J/kg ⋅K)( −25.0 C°)]$ $Q = −8.09 × 10^5 J $ The negative sign indicates heat is removed from the water. (b) Energy consumed in terms of Work $K = \frac{Q_C}{|W|}$ $|W| = \frac{−8.09 × 10^5 J }{2.40 }$ $|W| = 3.37 × 10^5 J $ (c) $|𝑄_𝐻| = W + |𝑄_𝐶|$ $|𝑄_𝐻| = 3.37 × 10^5 J + 8.09 × 10^5 J $ $|𝑄_𝐻| = 1.15 \times 10^6 J $