Reactions

Why must chemical reactions be balanced?

• For every action there is an equal and opposite reaction

• Matter cannot be created nor destroyed

• Reactants must release energy to the environment

• a. Compounds can be shown to dissolve in solution

In a chemical reaction there are 2Sr₃(PO₄)₂, how many oxygen atoms are present?

• Two Oxygen atoms

• Four Oxygen atoms

• Eight Oxygen atoms

• Sixteen Oxygen atoms

This is an unbalanced chemical reaction: C₆H₁₂O₆ + O₂ --> CO₂ + H₂O Which choice below shows this reaction as balanced?

• C₆H₁₂O₆ + 6O_{2 -->} 6CO₂ + 6H₂O

• C₆H₁₂O₆ + O₂ --> CO₂ + 3H₂O

• C₆H₁₂O₆ + 4O₂ --> 2CO₂ + H₂O

• C₆H₁₂O₆ + 3O₂ --> 2CO₂ + H₂O

This is an unbalanced chemical reaction: H₂ + N₂ --> NH₃ Which choice below shows this reaction as balanced?

• H₂ + 2N₂ --> 2NH₃

• 3H₂ + N₂ --> 2NH₃

• 4H₂ + 4N₂ --> NH₃

• H₂ + 4N₂ --> NH₃

This is an unbalanced chemical reaction: Cl₂ + NaBr --> NaCl + Br₂ Which choice below shows this reaction as balanced?

• Cl₂ + 4NaBr --> NaCl + 2Br₂

• 2Cl₂ +NaBr --> 2NaCl + Br₂

• Cl₂ + 2NaBr --> 2NaCl + Br₂

• Cl₂ + 2NaBr --> 6NaCl + Br₂

Which is NOT true when balancing a reaction?

• Subscripts can be changed within a chemical formula

• Coefficients can be changed in front of a chemical formula

• The number of atoms in the reactants and products must be equal

• The type of atoms in the reacts and products must be the same

What type of chemical reaction is this reaction? Na₂O + CO_{2 -->} Na₂CO₃

• Single replacement

• Double replacement

• Synthesis reaction

• Decomposition reaction

What type of chemical reaction is this reaction? Fe + O₂ --> Fe₂O₃

• Single replacement

• Double replacement

• Synthesis reaction

• Decomposition reaction

What are the possible products of a combustion reaction?

• Hydrocarbon and diatomic Oxygen

• Oxygen, Carbon, and light

• Water, Carbon dioxide, and heat

• Salt, Water, and hydronium

Name this compound: H2S04

• Citric acid

• Sulfuric acid

• Acetic acid

• Hydrogen sulfide