Question

A student performs an experiment in which 5.0 g of potassium chloride, KCI, are dissolved into 100.0 mL of distilled water. The student records the

temperature both before and after dissolving the KCl into the water, as shown in the data table below. Use this data to answer the question that follows.
Initial Temperature, °C Final Temperature, °C
21.8°C
16.4°C
Which statement below is a correct conclusion based on these results ?
The temperature of the water decreases and so the reaction is exothermic
The temperature of the water increases and so the reaction is exothermic
The temperature of the water decreases and so the reaction is endothermic
The temperature of the water increases and so the reaction is endothermic

Answer 1

The temperature of the water decreases and so the reaction is endothermic

Step-by-step explanation:

This option is correct because when the 5.0g potassium chloride (KCl) was added to the 100.0ml distilled water, the KCl made the water absorb heat coming from it which made the water decrease in temperature thereby causing an endothermic reaction.

An endothermic reaction actually takes place when the temperature of a system which is isolated decreases. The surroundings of a non-isolated system actually gains heat. While in an exothermic reaction, the temperature of a system increases due to the release or evolution of heat. This heat is released into the surroundings.