A student measured the temperature of a reaction mixture at the start and at the end of a reaction. Fig. 8.1 shows the thermometer at the start and Fig. 8.2...
Question 1 Report
A student measured the temperature of a reaction mixture at the start and at the end of a reaction. Fig. 8.1 shows the thermometer at the start and Fig. 8.2 shows the thermometer at the end.
Fig. 8.1
Fig. 8.2
(a) Read the temperature shown in Fig. 8.1. [1]
(b) Read the temperature shown in Fig. 8.2. [1]
(c) Calculate the temperature change during the reaction. [1]
(d) Name the apparatus used to measure temperature. [1]
Answer Details
This question tests reading a thermometer scale and finding a temperature change. On the scale shown, the numbered lines are every 10 °C and each small division is 2 °C.
(a) At the start the liquid reaches just above the 20 °C mark, reading about 21 °C (accept 20 to 22) [1].
(b) At the end the liquid reaches just above the 30 °C mark, reading about 31 °C (accept 30 to 32) [1].
(c) The temperature change is the final temperature minus the starting temperature: \( 31 - 21 = 10\ \degree\text{C} \) [1]. The temperature rose, so this reaction is exothermic (it releases heat to the mixture).
(d) The apparatus used to measure temperature is a thermometer [1]. Read it at eye level, level with the top of the liquid, to avoid parallax error.
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