Chem.ch7.exam3

Synthesis: (A + B --> AB); 2 H2 + O2 --> 2 H2O

Decomposition: (AB --> A + B); 2NaN3 --> 2 Na + 3 N2

• Single-displacement: (A + BC --> AC + B)
• Zn(s) + CuSO4(aq) --> Cu(s) + ZnSO4(aq)

• Double-displacement: (AB + CD --> AD + CB)
• Pb(NO3)2(aq) + 2 KI(aq) --> PbI2(s) + 2 KNO3(aq)

Precip: a solid or precip. forms upon mixing two (aq) solutions.

Acid-Base: Water forms upon mixing an acid and a base.

Gas evo: A gas forms upon mixing two (aq) solutions.

Redox: e- are transferred from one substance to another.

Combustion: A substance reacts w/ O2, emitting heat, and forming an oxygen-containing compound and, in many cases, water.

• Given: 17. g Nan
• Find: g Na2O

17.4 g Na x 1 mol Na/22.99 g Na (x) 2 mol Na2O/4 mol Na (x) 61.98 g Na2O/1 mol Na2O =

23.5 g Na2O

• Given: 4.8 mol Na
• Find: mol Na2O

4.8 mol Na x 2 mol Na2O / 4 mol Na =

2.6 mol Na2O

grams (x) <--> moles (x) <--> moles (y)<--> grams (y)

between g (x) and mol (x): molar mass of (x)

between mol (x) and mol (y): MOLE RATIO from balanced equation.

between mol (y) and g (y): molar mass of (y)