Chemical Equations

Chemical equations Represent chemical change Reactants Products (Starting (Substances Materials) Produced)

Procedure Identify all reactants and products E.g Magnesium(R) reacts with hydrochloric acid(R) to give magnesium chloride (P) and hydrogen gas.(P) Write a “word equation” Magnesium + Hydrochloric  Magnesium C acid chloride + hydrogen Convert each substance from a name to a formula Mg + HCl  MgCl 2 + H 2 (2 atoms together)

Balance the equation Use (big)numbers before the formula (this applies to the whole of the formula) Mg + 2HCl  MgCl 2 + H 2 Using 2HCl gives the same amount of H’s and Cl’s on each side (Mg’s are OK). The equation is now balanced. Hint: Leave uncombined elements until last

Another example Hydrogen + Oxygen  Water H 2 + O 2  H 2 O H 2 + O 2  2 H 2 O

Useful website – found through Google. Try to find more if you can – let us know! uiz/elemQuiz.htm uiz/elemQuiz.htm