Problem

Problem

A piece of brass is held in the flame of a Bunsen burner for several minutes. The brass is then quickly transferred into an aluminium calorimeter which contains 200.00 g of water. Determine the temperature of the Bunsen flame from the following data.
m(water) / ±0.01\pm 0.01 g200.00
m(brass) / ±0.01\pm 0.01 g212.10
m(aluminium calorimeter) / ±0.01\pm 0.01 g80.00
c(brass) / J g −1^{-1} K −1^{-1}0.400
c(Al) / J g −1^{-1} K −1^{-1}0.900
Initial temperature of water / ±0.1\pm 0.1 °C24.5
Final temperature of water / ±0.1\pm 0.1 °C77.5
Intuitive explanation

This is a calorimetry problem where you use energy conservation to find an unknown initial temperature. The key insight is that heat lost by the hot brass equals heat gained by the cooler water and calorimeter together—set up the energy balance equation qlost=qgainedq_{\text{lost}} = q_{\text{gained}}, then solve for the brass's starting temperature (which was the flame temperature). Remember to include both the water and the aluminium calorimeter as heat absorbers, since they both warmed up.

Intuitive explanation

This is a calorimetry problem where you use energy conservation to find an unknown initial temperature. The key insight is that heat lost by the hot brass equals heat gained by the cooler water and calorimeter together—set up the energy balance equation qlost=qgainedq_{\text{lost}} = q_{\text{gained}}, then solve for the brass's starting temperature (which was the flame temperature). Remember to include both the water and the aluminium calorimeter as heat absorbers, since they both warmed up.

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