1.21 write word equations and balanced chemical equations to represent the reactions studied in this specification

BALANCED EQUATIONS:

- A chemical equation can be used to show reactants to products in the form of word or symbol equations.

- Symbol equations must be balanced; there must be equal number of atoms on each side. To do this you add numbers in front of the formulae.
E.g:
copper + oxygen --> copper(II) oxide
Cu + O2 --> CuO
- However this isn't balanced so you add numbers.
- There are 2 oxygens so you need to make CuO x2 ; it becomes 2CuO. This still isn't balanced as we have Cu + O2 --> 2CuO. This now tells us that there are 2 coppers so we simply do Cu x2 to make 2Cu.
- The final correct equation is 2Cu + O2 --> 2CuO