Chemical Reactions Test Study Guide

To predict products and balance equations, follow these steps, with examples from the provided text:

Identify the Type of Reaction:
- Determine whether the reaction is synthesis, decomposition, single exchange, double exchange, or combustion.
Predict the Products:
- Synthesis: Two or more reactants combine to form a single product. $A + B \rightarrow AB$
 - Example: $Al + O2 \rightarrow Al2O_3$
- Decomposition: A single reactant breaks down into two or more products. $AB \rightarrow A + B$
 - Example: $HgO \rightarrow Hg + O_2$
- Single Exchange: One element replaces another in a compound. $A + BC \rightarrow AC + B$
 - Example: $Mg + Ag2SO4 \rightarrow MgSO_4 + Ag$
- Double Exchange: Two compounds exchange ions or elements. $AB + CD \rightarrow AD + CB$
 - Example: $K2SO4 + Ca(NO3)2 \rightarrow CaSO4 + KNO3$
- Combustion: A substance reacts rapidly with an oxidant (usually oxygen) to produce heat and light. $Fuel + O2 \rightarrow CO2 + H_2O$
 - Example: $C5H{10} + O2 \rightarrow CO2 + H_2O$
Write the Unbalanced Equation:
- Write the chemical formulas for all reactants and predicted products.
Balance the Equation:
- Use coefficients to ensure the number of atoms for each element is the same on both sides of the equation. Start with elements that appear in only one reactant and one product.
- Example: Balancing $HgO \rightarrow Hg + O_2$
 - Unbalanced: $HgO \rightarrow Hg + O_2$
 - Balanced: $2HgO \rightarrow 2Hg + O_2$
- Atom Inventory: Hg: 2 on the left, 2 on the right; O: 2 on the left, 2 on the right.
- Example: Balancing $Mg + Ag2SO4 \rightarrow MgSO_4 + Ag$
 - Unbalanced: $Mg + Ag2SO4 \rightarrow MgSO_4 + Ag$
 - Balanced: $Mg + Ag2SO4 \rightarrow MgSO_4 + 2Ag$
- Atom Inventory: Mg: 1 on the left, 1 on the right; Ag: 2 on the left, 2 on the right; S: 1 on the left, 1 on the right; O: 4 on the left, 4 on the right.
- Example: Balancing $C5H{10} + O2 \rightarrow CO2 + H_2O$
 - Unbalanced: $C5H{10} + O2 \rightarrow CO2 + H_2O$
 - Balanced: $2C5H{10} + 15O2 \rightarrow 10CO2 + 10H_2O$
- Atom Inventory: C: 10 on the left, 10 on the right; H: 20 on the left, 20 on the right; O: 30 on the left, 30 on the right.
- Example: Balancing $K2SO4 + Ca(NO3)2 \rightarrow CaSO4 + KNO3$
 - Unbalanced: $K2SO4 + Ca(NO3)2 \rightarrow CaSO4 + KNO3$
 - Balanced: $K2SO4 + Ca(NO3)2 \rightarrow CaSO4 + 2KNO3$
- Atom Inventory: K: 2 on the left, 2 on the right; S: 1 on the left, 1 on the right; O: 12 on the left, 12 on the right; Ca: 1 on the left, 1 on the right; N: 2 on the left, 2 on the right.
- Example: Balancing $Al + O2 \rightarrow Al2O_3$
 - Unbalanced: $$Al + O2 \rightarrow Al