WorksheetsUnderstanding Chemical Equations
Total questions: 10
Worksheet time: 5mins
What is the law of conservation of mass in relation to balancing chemical equations?
The law of conservation of mass requires that the number of atoms for each element is equal on both sides of a balanced chemical equation.
The law of conservation of mass states that mass can be created or destroyed in a chemical reaction.
Balancing chemical equations is only necessary for reactions involving gases.
The law of conservation of mass applies only to solid substances in a chemical reaction.
Balance the following equation: H2 + O2 → H2O.
2 H2 + O2 → 2 H2O
H2 + 2 O2 → H2O2
2 H2 + O2 → H2
H2 + O2 → H2O
Identify the type of reaction: 2Na + Cl2 → 2NaCl.
Combination reaction
Decomposition reaction
Single displacement reaction
Double displacement reaction
What are the four main types of chemical reactions?
Synthesis, Decomposition, Single Replacement, Double Replacement
Neutralization
Photolysis
Combustion
Redox
Balance the equation: C3H8 + O2 → CO2 + H2O.
C3H8 + 2 O2 → CO2 + H2O
C3H8 + 4 O2 → 3 CO2 + 5 H2O
C3H8 + 5 O2 → 3 CO2 + 4 H2O
C3H8 + 3 O2 → 2 CO2 + 3 H2O
What is a synthesis reaction? Provide an example.
An example of a synthesis reaction is the formation of water: 2H2 + O2 → 2H2O.
A synthesis reaction occurs when two substances are mixed without any chemical change: NaCl + H2O.
A decomposition reaction is the breakdown of water: 2H2O → 2H2 + O2.
An example of a synthesis reaction is the combustion of methane: CH4 + 2O2 → CO2 + 2H2O.
Describe a decomposition reaction and give an example.
An example of a decomposition reaction is the electrolysis of water, which produces hydrogen and oxygen gases.
An example of a decomposition reaction is the combustion of methane, producing carbon dioxide and water.
A decomposition reaction occurs when a substance is heated to form a new compound.
A decomposition reaction combines two or more substances to form a single product.
How do you identify a single replacement reaction?
A single replacement reaction occurs when two elements combine to form a compound.
A single replacement reaction involves two compounds exchanging elements.
A single replacement reaction is identified by one element replacing another in a compound.
A single replacement reaction is characterized by the formation of a gas or precipitate.
Balance the following equation: Fe + O2 → Fe2O3.
2 Fe + O2 → Fe2O3
3 Fe + 2 O2 → Fe2O3
4 Fe + 2 O2 → 2 Fe2O3
4 Fe + 3 O2 → 2 Fe2O3
What distinguishes an exothermic reaction from an endothermic reaction?
Exothermic reactions absorb energy; endothermic reactions release energy.
Both exothermic and endothermic reactions release energy.
Exothermic reactions do not involve energy changes; endothermic reactions do.
Exothermic reactions release energy; endothermic reactions absorb energy.
