Chemical Reactions Review

What are the missing coefficients for the skeleton equation below?

N₂ +H₂ → NH₃

• 1,1,2

• 1,3,3

• 3,1,2

• 1,3,2

• 2,6,6

Answer explanation

1N₂ +3H₂ → 2NH₃

_{N - 2 on each side}

_{H - 6 on each side}

When the following equation is balanced, what is the coefficient for HCl?

Mg (s) + HCl (aq) → MgCl₂ (aq) + H₂(g)

• 1

• 2

• 3

• 4

Answer explanation

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

Mg - 1 on each side

H - 2 on each side

Cl - 2 on each size

__ AgI + __ Na₂S → __ Ag₂S + __ NaI

• AgI + Na₂S → Ag₂S + 2 NaI

• 2 AgI + 2 Na₂S → 2 Ag₂S + 2 NaI

• 2 AgI + 2 Na₂S → Ag₂S + 2 NaI

• 2 AgI + Na₂S → Ag₂S + 2 NaI

Answer explanation

2 AgI + Na₂S → Ag₂S + 2 NaI

Ag - 2 on each side

Na - 2 on each side

S - 1 on each side

I - 2 on each side

Iron reacts with chlorine to form iron (III) chloride. The balanced chemical equation for this reaction is:

• 2Fe + 3Cl₂ → 2FeCl₃

• Fe + Cl₂→ FeCl₂

• 2Fe + Cl₂ → 2FeCl₃

• 2Fe + Cl₂ → 2FeCl

Answer explanation

Iron (II) has a 2+ charge, and chloride has a 1- charge, so FeCl₂ balances the charges.

The activity series of metals is used to determine whether or not a ______ reaction has occurred.

• combustion

• single replacement

• double replacement

• synthesis

Evidence that a reaction has occurred includes

• A change of color

• Gas formation

• Temperature change

• A new smell

What type of reaction is SiO₂ + HF → SiF₄ + H₂O

• synthesis

• double replacement

• decomposition

• single replacement

What type of reaction is Al + O₂ → Al₂O₃

• Synthesis

• Decomposition

• Double Replacement

• Single Replacement

Answer explanation

Multiple reactants forming one produce is a synthesis reaction

Identify the type of chemical reaction demonstrated by this equation:

2KClO₃ → 2KCl + 3O₂

• synthesis

• decomposition

• single replacement

• double replacement

Answer explanation

One reactant forming multiple products is a decomposition reaction

What are the products of this reaction? Ca + O₂ →

• CaO

• CaO₂

• Ca₂O

• cow

Answer explanation

Calcium forms a Ca²⁺ ion, and oxygen forms a O^2- ion, so CaO has balanced charges.