Ch. 8 Objectives

1. Evolution of heat and light. Production of a gas. Formation of a precipitate.
2. The equation must represent known facts. The equation must contain the correct formulas for the reactants and products. The law of conservation of mass must be satisfied.
3. 1. Start with the most complicated compound. Assume there’s only one molecule of this compound in the reaction.
2. Start balancing atoms present in the lowest number of compounds.
3. Balance atoms present in most compounds at the end.
4. Once all atoms and charges are balanced, remove fractions and find set of the smallest coefficients.
4. Synthesis: The general form of a synthesis reaction is A + B → AB. Synthesis reactions "put things together.”
Decomposition: Opposite of synthesis, with the format AB → A + B. Decomposition reactions "take things apart."
Single-displacement: Reactions swap one component with another, in the format AB + C → AC + B.
Double displacement: Reactions where two compounds swap components, in the format AB + CD → AD + CB.
5. Synthesis: The combination of 2 or more simple substances to form a more complex substance.
Decomposition: Two or more simpler substances form when a complex compound breaks apart.
Single-displacement: Replacement of a metal in a compound by a more active metal.
Double-displacement: Compound + Compound --> Compound + Compound
Combustion: When oxygen combines with another compound to form water and carbon dioxide.
6. Synthesis: Water: 2 H2(g) + O2(g) → 2 H2O(g)
Carbon Dioxide: 2 CO(g) + O2(g) → 2CO2(g)
Ammonia: 3 H2(g) + N2(g) → 2 NH3(g)
Decomposition: H2CO3 → H2O + CO2
Ca(OH)2 → CaO + H2O
Li2CO3 → Li2O + CO2
2KClO3 → 2KCl + 3O2
2HgO → 2Hg + O2
2NaCl → 2Na + Cl2
7. Single-displacement: Cu + AgNO3 → Ag + Cu(NO3)2
Fe + Cu(NO3)2 → Fe(NO3)2 + Cu
Ca + H2O → Ca(OH)2 + H2
Zn + HCl → ZnCl2 + H2
Double-displacement: KOH + H2SO4 ---> K2SO4 + H2O
FeS + HCl ---> FeCl2 + H2S
NaCl + H2SO4 ---> Na2SO4 + HCl
8. 1. Write down the cations and anions present in each of the reactants.
2. Swap the ions to build the products.
3. Label the products as solid, liquid, or aqueous.
4. Does a reaction occur?
5.Balance the equation.