Final answer:
The temperature change in the thermochemistry experiment should be recorded as 18.9 ± 1.0°C, calculated by subtracting the initial temperature from the maximum temperature and adding the uncertainties of each measurement.
Step-by-step explanation:
To report the temperature change for the reaction in a thermochemistry experiment with the given uncertainties, you first calculate the difference between the maximum temperature and the initial temperature. Then, you combine the uncertainties of the two temperature measurements to find the total uncertainty in the temperature change. The initial temperature is 18.7 ± 0.5°C, and the maximum temperature is 37.6 ± 0.5°C.
The temperature change (ΔT) is calculated as:
- Maximum temperature - Initial temperature = 37.6°C - 18.7°C = 18.9°C
To find the combined uncertainty, you add the absolute uncertainties of the initial and final measurements since they are of the same type (type A) and directly related to the temperature change:
- Combined uncertainty = 0.5°C + 0.5°C = 1.0°C
Therefore, the temperature change should be recorded as:
18.9 ± 1.0°C