A 406.0 kg copper bar is put into a smelter for melting.The initial temperature of the copper is 300.0 K.How much heat must the smelter produce to completely melt the copper bar? (The specific heat for copper is 386 J/kg ∙ K,the heat of fusion for copper is 205 kJ/kg,and its melting point is 1357 K.)

Question

Quizplus · Accepted Answer

The correct answer is A because the heat required to melt the copper bar is equal to the sum of the heat required to raise the temperature of the copper from 300.0 K to its melting point of 1357 K and the heat of fusion of copper. The heat required to raise the temperature of the copper is given by:Q1 = m * c * (Tf - Ti)where m is the mass of the copper bar, c is the specific heat of copper, Tf is the melting point of copper, and Ti is the initial temperature of the copper.Q1 = (406.0 kg) * (386 J/kg ∙ K) * (1357 K - 300.0 K) = 1.66 × 10^8 JThe heat of fusion of copper is the amount of heat required to melt 1 kg of copper at its melting point. The heat of fusion of copper is given by:Q2 = m * Lfwhere m is the mass of the copper bar and Lf is the heat of fusion of copper.Q2 = (406.0 kg) * (205 kJ/kg) = 8.32 × 10^7 JThe total heat required to melt the copper bar is:Q = Q1 + Q2 = 1.66 × 10^8 J + 8.32 × 10^7 J = 2.49 × 10^8 J

A 4060 Kg Copper Bar Is Put into a Smelter for for Melting.The