Question

You place a thermometer in a water bath holding a flask in which you will carry out a reaction. The temperature of the water bath before the reaction is 22°C. You pour the reactants into the flask for the reaction. Knowing this is an endothermic reaction, which of the following temperature values could you expect at the end of the reaction?

a) 20°C
b) 22°C
c) 23°C
d) 25°C

Answer 1

For an endothermic reaction, the temperature of the surroundings decreases because the reaction absorbs heat from the surroundings. Starting at 22°C, the temperature would drop, thus the plausible temperature after the reaction is 20°C. Therefore, the correct answer is (a) 20°C.

Step-by-step explanation:

Since the reaction taking place in the flask is endothermic, it will absorb heat from the surroundings. This means that the temperature of the water in the water bath surrounding the flask would decrease as the reaction proceeds, due to heat being transferred from the water to the reactants. The initial temperature of the water bath is 22°C, so at the end of the endothermic reaction, a plausible temperature you could expect would be lower than 22°C. Therefore, the correct answer is (a) 20°C.

An endothermic reaction absorbs heat from the surroundings, so the temperature of the water decreases as heat leaves the surroundings to enter the system. In this case, the initial temperature of the water bath is 22°C. Since the reaction is endothermic, we can expect the temperature at the end of the reaction to be lower than the initial temperature. From the given options, the most likely temperature value at the end of the reaction would be 20°C.