Reaction Rules

REACTION RULES

SYNTHESIS:

1. O2 + many metals----metallic oxides example: 4Li + O2-----2 Li2 O 2. non-metals + nonmetals----molecular compounds (covalently bonded)

example: C +O2 -----CO2 3. metals + non-metals---- salts (usually)

but metals + O2-----oxides, not salts

example: Ca + Cl2-----Ca Cl2 (a salt);

however, 2Ca + O2--- 2CaO (an oxide) 4. non-metallic oxides + water--oxyacid

example: N2O5 + H2O -----2HNO3

5. active metallic oxides + H2O------metallic hydroxides

example: Na2O + H2O -----2NaOH

6. some metallic oxides + non-metallic oxides----salt

example: CaO + CO2 -----CaCO3

DECOMPOSITION:

1. metallic oxides of less active metals + heat------O2 + metal

example: Ag2O + heat-----Ag + O2

2. metallic carbonates + heat----metallic oxide + CO2

example: CaCO3 + heat-----CaO + CO2

3. metallic hydroxides + heat----metallic oxide + H2O

example: Ca(OH)2 + heat-----CaO + H2O

4. metallic chlorates (bromates, iodates, etc) + heat—salts + O2

example: 2NaClO3 + heat -----2NaCl + 3O2

5. some acids (H2SO4, H2CO3) + heat------non-metallic oxides + water

example: H2CO3 + heat -----CO2 + H2O

DOUBLE REPLACEMENT:

1. requires regrouping of at least two ions into a new product. 2. reactants involved must be either soluble in water or soluble one in the other 3. new product should be a precipitate, water, and or a gas 4. in reactions involving a strong acid with a strong base, water is a product

SINGLE REPLACEMENT:

1. more active metals replace ions if less reactive ones (bumping chart) example: Li(s) + Na+ ----- Li+ + Na (s) 2. more active halogens replace less reactive ones - - example: Cl2 + 2Br ----- 2Cl + Br2 3. active metals in group 1 and some in group 2 react with HOH----metallic

hydroxides and H2 gas + - example: 2Na + 2HOH----Na + 2OH + H2

4. less active metals such as iron + HOH----metallic oxide + H2

example: 2Fe + 3HOH------Fe2O3 + 3H2

5. active metals + some acids (HCl, dilute H2SO4)------salts + H2

example: 2Na+ 2HCl(aq)-----2NaCl+H2 Activity Series of Metals (Bumping Chart)

Li *Can react with water and acids to produce a metallic hydroxide and hydrogen gas. Rb K Ba Sr Ca Na Mg Al Mn Can react with Zn steam and acids Cr replacing hydrogen. Fe Cd Co Ni Sn Can react with Pb acids, replacing hydrogen

H2 Sb React with oxygen Bi forming oxides. Cu Hg Ag Fairly non-reactive Pt Form oxides only Au indirectly.

Activity of Halogen Nonmetals

OTHER RULES TO CONSIDER:

1. Using the reactivity series (bumping chart), atoms of a metal will lose electrons to ions of metals below that metal on the chart in an oxidation/reduction event.

2. Metals above Mg on the chart will react with water to yield H2 gas.

3. Metals above Co but below Mg on the chart will react with steam to yield H2 gas.

4. Metals will react with acids to yield H2 gas and the salt (composed of the metal cation and the acid ion). 5. The more active the metal (the higher up on the chart) the better chance of making an oxide from direct contact with oxygen gas. Metals below Hg on the chart form oxides only indirectly. 6. Oxides of the active metals resist decomposition due to their great attraction for oxygen. On the chart below Cu, heat alone is needed to decompose CuO; below Cr, hydrogen and heat are needed. NiO(s) + H2(g)------Ni(s) + HOH 7. Active metals are not found free in nature; elements at the bottom of the activity chart (bumping chart) are due to their overall poor reactivity.