For a 2 kg substance with specific heat capacity c = 4184 J/(kg·K) that undergoes a temperature change ΔT = 5 K, how much heat Q is transferred?

• A. 41840 J
• B. 20920 J
• C. 8368 J
• D. 10460 J

Answer: (A)

Heat transferred depends on how much mass changes temperature, how resistant that substance is to heating (its specific heat), and how much the temperature changes: Q = m c ΔT. Here mass is 2 kg, specific heat is 4184 J/(kg·K), and the temperature change is 5 K. Multiply step by step: m c = 2 × 4184 = 8368 J/K, then Q = 8368 × 5 = 41840 J. The Kelvin and Celsius scales give the same numerical ΔT, so the 5 K change directly scales the heat. The result is in joules, as expected. If the temperature change were smaller, or the mass or c were smaller, the heat would be proportionally smaller.