Question

When a cold pack is used, ammonium chloride mixes with water and energy is absorbed from the water to reduce the temperature of the water. Which of the following describes this type of reaction?
A. Endothermic
B. Exothermic
C. Decomposition
D. Synthesis

Answer 1

I think the answer is Endothermic. Since the question says "absorbs," endo means to "go in" sort of and exo means to exit.

exo = exit
endo = enter
(A trick my teacher taught us)

Sorry if I'm wrong, hope I helped. :)

Answer 2

Answer: A. Endothermic

Explanation:

Endothermic reactions are defined as the reactions in which energy of the product is greater than the energy of the reactants. The total energy is absorbed in the form of heat and $\Delta H$ for the reaction comes out to be positive.

Exothermic reactions are defined as the reactions in which energy of the product is lesser than the energy of the reactants. The total energy is released in the form of heat and $\Delta H$ for the reaction comes out to be negative.

Decomposition is a chemical reaction in which one reactant gives two or more than two products,

Synthesis is a chemical reaction in which two or more than two reactants gives one products.