Energy required to heat 250 g iron from 20°C to 60°C with c = 450 J/kg°C?

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Multiple Choice

Energy required to heat 250 g iron from 20°C to 60°C with c = 450 J/kg°C?

The energy needed to heat something depends on its mass, how much the temperature is changed, and how much energy is required to raise the temperature per kilogram per degree. This is captured by Q = m c ΔT. Convert mass to kilograms: 250 g = 0.25 kg. The temperature change is ΔT = 60°C − 20°C = 40°C. Plug into the formula: Q = 0.25 kg × 450 J/(kg·°C) × 40°C. Calculate: 0.25 × 450 = 112.5; 112.5 × 40 = 4500 J. So the energy required is 4500 J. The other numbers would come from using a different ΔT (for example, a 20°C rise would give 2250 J, a 32°C rise would give 3600 J, or an 8°C rise would give 900 J).

The energy needed to heat something depends on its mass, how much the temperature is changed, and how much energy is required to raise the temperature per kilogram per degree. This is captured by Q = m c ΔT.

Convert mass to kilograms: 250 g = 0.25 kg. The temperature change is ΔT = 60°C − 20°C = 40°C. Plug into the formula: Q = 0.25 kg × 450 J/(kg·°C) × 40°C.

Calculate: 0.25 × 450 = 112.5; 112.5 × 40 = 4500 J. So the energy required is 4500 J.

The other numbers would come from using a different ΔT (for example, a 20°C rise would give 2250 J, a 32°C rise would give 3600 J, or an 8°C rise would give 900 J).

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