High School Chemistry : Help with Dissociation Reactions

Study concepts, example questions & explanations for High School Chemistry

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Example Questions

Example Question #1 : Help With Dissociation Reactions

What is another term for a dissociation reaction?

Possible Answers:

Single-replacement reaction

Double-replacement reaction

Synthesis reaction

Dehydration reaction

Decomposition reaction

Correct answer:

Decomposition reaction

Explanation:

Dissociation reactions occur when one molecule is divided to form two smaller ones, leading to a decrease in energy. Dissociation reactions result in the break down of a large molecule to form smaller products, giving them their second name: decomposition reactions.

Many decomposition reactions can also be classified as hydrolysis reactions, if water is used as a reactant. One example of this is the breakdown of glycogen to form glucose monomers. Dehydration reactions release water in order to form a new bond, building a larger molecule from smaller reactants (synthesis).

Example Question #131 : Reactions And Equilibrium

The reaction above could be classified as __________.

Possible Answers:

single displacement

decomposition 

decomposition and oxidation-reduction

synthesis

oxidation-reduction

Correct answer:

decomposition 

Explanation:

When one molecule is converted into two or more smaller molecules, the reaction is considered a decomposition reaction. In this example, none of the elements under go a change in oxidation number, so this is not an oxidation-reduction reaction. (Calcium is always , oxygen is always , and carbon remains  throughout the reaction.)  

Example Question #2 : Help With Dissociation Reactions

In a dissociation reaction, determine the potential products for:

Possible Answers:

Correct answer:

Explanation:

Dissociation reactions usually entail a salt or ionic compounds dissociating or splitting into its components. In this case,  where AB is made up of the components A and B. This reaction is ideally reversible even though the question does not provide the reversible arrows. 

The options that include a third species, would be incorrect, as there are only two species in the original compound that is dissociating. 

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