A 150 g block of copper is heated from 20.0 °C to 100.0 °C. The specific heat capacity of copper varies with temperature as shown:
• 20–50 °C: 0.386 J g⁻¹ °C⁻¹
• 50–80 °C: 0.382 J g⁻¹ °C⁻¹
• 80–100 °C: 0.380 J g⁻¹ °C⁻¹
(1) Calculate the total heat, in kilojoules, absorbed by the copper during the entire heating.
(2) Identify which temperature interval contributes the greatest portion of the total heat and state that portion as a percentage of the total.