Reporting Category: Bonding and Reactions Standard: 5.1 - Balance chemical equations by applying the laws of conservation of mass and constant composition (definite proportions).
Standard: 5.2 - Classify chemical reactions as synthesis (combination), decomposition, single displacement, double displacement, and combustion.
Five chemical reactions are listed in the table below.
CaCO3 → CaO + CO2
Ca(OH)2 + 2HCl → CaCl2 + 2H2O
NH3 + HCl → NH4Cl
PbO2 → Pb + O2
2Mg + O2 → 2MgO
Identify one chemical reaction from the list that is a synthesis (combination) reaction. Explain why you identified this reaction as synthesis.
Identify one chemical reaction from the list that is a decomposition reaction. Explain why you identified this reaction as decomposition.
Describe a combustion reaction.
Write a balanced chemical equation for a combustion reaction using some or all of the substances from the table below.
Scoring Guide and Sample Student Work Select a score point in the table below to view the sample student response.
The response demonstrates a thorough understanding of how to classify chemical reactions. The response correctly identifies one example of a synthesis (combination) reaction and one example of a decomposition reaction and clearly explains each answer. The response also correctly describes a combustion reaction and gives a balanced chemical equation for a combustion reaction.