Chemical Equations Learning Objective: To write and explain chemical equations.

Chemical Equations Learning Outcomes Good if you are able to interpret word equations. Even better if you are able to use molecular models to represent reactions. Great if you can write word equations and use as part of an explanation. Out of this world if you can write balanced symbol equations.

WORD EQUATIONS REACTANTS PRODUCTS Word equations are a short way of describing reactions They are written in the format: REACTANTS PRODUCTS The substances that react together The substances that are made

WORD EQUATIONS magnesium + oxygen magnesium oxide example When magnesium burns it reacts with the oxygen in the air to make magnesium oxide Identify the reactants Write them on the left hand side Identify the products Write them on the right hand side magnesium + oxygen magnesium oxide

WORD EQUATIONS sodium + chlorine sodium chloride example White crystals of sodium chloride are formed when green chlorine gas is reacted with sodium metal. Identify the reactants Write them on the left hand side Identify the products Write them on the right hand side sodium + chlorine sodium chloride Use names only!

WORD EQUATIONS Common Mistakes sulphate zinc + copper Zinc reacts with blue copper sulphate solution to form colourless zinc sulphate and copper sulphate zinc + copper zinc sulphate + copper use full name

WORD EQUATIONS calcium carbonate hydrochloric acid Common Mistakes When calcium carbonate is added to hydrochloric acid, the solution bubbles making calcium chloride, water and carbon dioxide calcium carbonate + hydrochloric acid water calcium chloride + carbon dioxide Reactants on left of arrow, all products on the right of the arrow calcium chloride carbon dioxide calcium carbonate hydrochloric acid + + + water

However FORMULA EQUATIONS REACTANTS PRODUCTS These equations use formula instead of names The formula are often given to you They are also written in the format: REACTANTS PRODUCTS However They need to be balanced. There needs to be the same number of each type of atom on both sides of the equation

2 Mg + O2 2 MgO FORMULA EQUATIONS When magnesium burns it reacts with the oxygen in the air to make magnesium oxide 2 Mg + O2 2 MgO Oxygen comes bonded to magnesium

2 Na + H2O 2 2 NaOH + H2 FORMULA EQUATIONS If sodium (Na) is added to water (H2O) sodium hydroxide (NaOH) and hydrogen gas (H2) are formed 2 Na + H2O 2 2 NaOH + H2 but a hydrogen comes joined to an oxygen and a hydrogen Can get these from here and get a sodium need another hydrogen need an oxygen and another hydrogen

Try These 2 2 3 2 3 Mg + O2 Zn + HCl Fe + Cl2 NaOH + HCl CH4 + O2 2 3 2 3 Mg + O2 Zn + HCl Fe + Cl2 NaOH + HCl CH4 + O2 Ca + H2O NaOH + H2SO4 CH3OH + O2 MgO ZnCl2 + H2 FeCl3 NaCl + H2O CO2 + H2O Ca(OH)2 + H2 Na2SO4 + H2O 2 2 4