types of reactions

two or more substances combine to form something more complex

general form: A + B → AB

examples:

2Na + Cl2 → 2NaCl

N2 + 3H2 → 2NH3

Fe + S → FeS

a reaction in which a single compound breaks down to form two or more simpler substances

general form: AB → A + B

examples:

CaCO3 → CaO + CO2

2H2O2 → 2H2O + O2

H2CO3 → H2O + CO2

one substance reacts with oxygen or a similar compound in a usually high-heat, exothermic reaction

general form: A + O2 → AO

examples:

2H2 + O2 → 2H2O

CH4 + 2O2 → 2H2O + CO2

2Mg + O2 → 2MgO

one atom or group of atoms is replaced by another

general form: AX + B → BX + A

examples:

CuCl + Na → NaCl + Cu

Al(OH3) + 3K → 3KOH + Al

ZnCl2 + 2Li → 2LiCl + Zn

two atoms or two groups of atoms switch places

general form: AX + BY → AY + BX

examples:

2KI + Pb(NO3)2 → 2KNO3 + PbI2

CuCl2 + 2NaOH → Cu(OH)2 + 2NaCl

MgSO4 + Na2CO3 → Na2SO4 + MgCO3