Chemical Reactions Test Review (FY23)

The reaction represented by the equation

Pb(NO₃)₂(aq) + 2KI(aq) → PbI₂(s) + 2KNO₃(aq) is a

• decomposition reaction.

• double-displacement reaction.

• synthesis reaction.

• combustion reaction.

• single-displacement reaction.

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Which of the following is the correct skeleton equation for the reaction that takes place when solid phosphorus combines with oxygen gas to form diphosphorus pentoxide?

• P(s) + O₂(g) → P₂O₅(s)

• P₂O₅(s) → P₂(s) + O₂(g)

• P(s) + O₂(g) → P₅O₂(g)

• P(s) + O₂(g) → PO₂(g)

In a combustion reaction, one of the reactants is _.

• carbon dioxide

• hydrogen

• water

• oxygen

When the equation Fe + Cl₂ → FeCl₃ is correctly balanced, what is the coefficient of Fe?

• 4

• 1

• 3

• 2

The reaction represented by the equation

Mg(s) + 2HCl(aq) → H₂(g) + MgCl₂(aq) is a

• single-replacement reaction

• combustion reaction

• decomposition reaction

• double-replacement reaction

In order to predict whether or not a single-replacement reaction takes place, you need to consult a chart that shows the __.

• periodic table

• ionic charges of the elements

• common polyatomic ions

• activity series of metals

In what kind of reaction do two or more substances combine to form a new compound?

• combustion

• single displacement

• double displacement

• synthesis

• decomposition

Two chemicals react together and one of the products turns into a gas. What symbol is used to indicate this?

• (s)

• (l)

• (aq)

• (g)

What type of reaction is taking place in this picture?

• Combination/Synthesis

• Decomposition

• Single replacement

• Double replacement

Which chemical equation shows the correct formulas and coefficients for this reaction:

A solution of potassium sulfide and hydrochloric acid react to form aqueous potassium chloride and hydrogen sulfide gas.

• K₂S (aq) + 2 HCl (aq) ⟶   2 KCl (aq) + H₂S (g)

• K₂S (aq) + HCl (aq) ⟶   KCl (aq) + H₂S (g)

• K₂S + HCl ⟶   KCl + H₂S

• K₂S + 2 HCl ⟶   2 KCl + H₂S