Question

Write the chemical equation for each reaction described below. Make certain it is balanced, then classify the reaction as Combination, Decomposition, Single-Replacement, Double-Replacement-Neutralization, Double-Replacement -precipitation, or Combustion.

Water is driven from copper sulfate pentahydrate with heat.

Answer 1

Combination Reaction

The general form of a Combination or synthesis reaction is A + B → AB. Synthesis reactions "put things together".

2H2 (g) + O2 (g) ------------> 2H2O (l)

Decomposition Reaction

These are the opposite of synthesis reactions, with the format AB → A + B. Decomposition reactions "take things apart". Just as synthesis reactions can only form one product, decomposition reactions can only start with one reactant.

2H2O2(l) -------------> 2H2O(l) + O2 (g)

Single Displacement Reaction

Single displacement reaction, is a reaction in which 2 elements are substituted for another element in a compound. The starting materials are always pure elements, such as a pure zinc metal or hydrogen gas plus an aqueous compound. When a displacement reaction occurs, a new aqueous compound and a different pure element are generated as products. Its format is AB + C → AC + B. Single Diplacement Adding hydrochloric acid to zinc will cause a gas to bubble out:

Zn (s) + 2 HCl(aq) ---------> ZnCl2 (aq) + H2 (g)

Double Displacement Reaction -Neutralization

In these reactions, two compounds swap components, in the format AB + CD → AD + CB

This is also called an "exchange". Here are the examples below:

HCl(aq) + NaOH(aq) ----> NaCl(aq)+ H2O(l)

Double Displacement Reaction -Precipitation

A precipitation reaction occurs when anionic substance comes out of solution and forms an insoluble (or slightly soluble) solid. The solid which comes out of solution is called a precipitate. This can occur when two soluble salts (ionic compounds) are mixed and form an insoluble one—the precipitate.

Pb( NO3)2_(aq) + 2 KI(aq) -------------> PbI_2(s) + 2 KNO3(aq)

Combustion Reaction

The combustion of methane (releasing heat and light)

Combustion, better known as burning, is the combination of a substance with oxygen. The products are carbon dioxide, water, and possible other waste products. Combustion reactions release large amounts of heat. C₃H₈, better known as propane, undergoes combustion. The balanced equation is:

${\displaystyle {\hbox{C}}_{3}{\hbox{H}}_{8}+5{\hbox{O}}_{2}\to 3{\hbox{CO}}_{2}+4{\hbox{H}}_{2}{\hbox{O}}}$

The reaction is like a decomposition reaction because you start with one substance and end up with two products.

It is also conidered a dehydration reaction because water is expelled from the starting substance.

CuSO4·5H2O(s) → CuSO4(s) + 5H2O(g)

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