TYPES OF CHEMICAL REACTIONS Displacement Polymerisation Combustion TYPES OF CHEMICAL REACTIONS Combination Precipitation Decomposition Neutralisation

Displacement Reactions Definition: Occurs when an element or ion moves out of one compound and into another

Displacement Reactions Examples: Silver nitrate + zinc  silver + zinc nitrate 2AgNO3 + Zn  2Ag + Zn(NO3)2 Nitrate moves from silver to zinc Magnesium + hydrochloric acid  magnesium chloride + hydrogen Chloride moves from hydrogen to magnesium Mg + 2HCl  MgCl2 + H2

Displacement Reactions Memory Trick: Deciding that you will ‘swap’ your boyfriend for someone better! Remember, an element becomes a compound, and a compound becomes an element A + BX  AX + B

Polymerisation Reactions Definition: Occurs when many repeating monomers link together to form a polymer Sometimes water is also produced Monomer: small molecule Polymer: large molecule made of repeating units

Polymerisation Reactions Example: C6H12O6 (glucose) + C6H12O6 (glucose)  C12H22O11 (sucrose) + H2O 2 glucose monomers are added to make sucrose and water

Neutralisation Reactions Definition: Two types of reactions: Acid + base  water + ionic compound Acid + metal carbonate  water + ionic compound + carbon dioxide An acid is a corrosive substance that contains H. A base is its chemical opposite and their chemical formula usually ends in OH Having the OH and H is what forms water An ionic compound is formed via ionic bonding

Neutralisation Reactions Examples: Acid + Base  water and ionic compound Hydrochloric acid (HCl) + sodium hydroxide (NaOH) (a base)  water (H2O) + sodium chloride (NaCl) Acid + metal carbonate  water + salt + carbon dioxide 2 HCl + CaCO3  H2O + CaO + CO2

Precipitation Reactions Definition: Occurs when a clear salt solution (aqueous solution) reacts with another salt solution and the ions swap partners to form an insoluble solid (or precipitate)

Precipitation Reactions Example: Silver nitrate + sodium chloride  silver chloride + sodium nitrate AgNO3 (aq) + NaCl(aq)  AgCl(s) + NaNO3 (aq) Silver nitrate and sodium chloride swap partners to become silver chloride and sodium nitrate

Precipitation Reactions Memory Trick: Think of two couples going out to the Year 10 social and leaving with each other’s partners XY + AZ  XZ + AY Partner 2a Partner 1a Partner 1b Partner 2b Result: 1a and 2b now partners 2a and 1b now partners

Precipitation Reactions Remember: A cation must end up with an anion Therefore, the first ion of one pair must end up with the second ion of the other pair i.e. Silver nitrate + sodium chloride must create silver chloride and sodium nitrate; it cannot produce silver sodium and nitrate chloride

Combination Reactions Definition: Two or more elements/compounds bond together to form a single substance Examples: Silver + oxygen  silver oxide 2Ag + O2  2AgO Carbon + oxygen  carbon dixode 2C + 2O2  2CO2

Combination Reactions Memory Trick: A couple getting married X + Y  XY

Decomposition Reactions Definition: Occurs when one compound (not an element) is heated, resulting in the compound breaking into individual atoms or molecules Examples: Calcium carbonate  calcium oxide + carbon dioxide CaCO3  CaO + CO2

Decomposition Reactions Memory Trick: The opposite of combination reactions One reactant, several products A married couple getting divorced XY  X + Y

Combustion Reactions Definition: Involves burning a reactant or fuel in oxygen Usually produces water and carbon dioxide Example: Fuel + oxygen  carbon dioxide + water CH4 + 3O2  CO2 + 2H2O