1. Two important principles to remember from last lesson…
Every chemical compound has a ___________ which can not be altered. You can only change the _____________________
A chemical reaction must account for ___________________________that is used because in a chemical reaction __________________
_____________________________________________.

2. Steps to Word Equations
Balancing word equations is very similar to balancing skeleton equations with one extra step…
…______________________________________________
_______________________________________________
Word equation: Iron (III) oxide + Hydrogen  Water + Iron
reactants
products
***Notice that common names are used (water) as well as the diatomic molecule Hydrogen***
Skeleton equation:

3. try and balance it yourself…
Let’s Balance It!
H2 + Fe2O3  H2O + Fe
H= 2
Fe = 2
O = 3 
H = 2
Fe = 1
O = 1
Counting the atoms on each side of the equation shows us that this skeleton equation is not balanced –
try and balance it yourself…
Balanced equation:

4. Hints for Doing Word Equations
Word equations require careful examination to be written correctly.
Always check your exam booklet for the ________________________of some of the covalent compounds (also called _____________________)
These are two that you will need to memorize:
Methane = _______
Ammonia = ________
The chemical _________ is used for most elements ________________.
E.g. If you see _________ in a word equation it is referring to ______
The ___________________ are the others you need to memorize:
E.g. If they said hydrogen in the equation they are referring to _____________________________
The others that we needed to remember were: ______________
______________________________________________________