Chemical Equations
Basic Chemical Equation
Chemical equations are vital in Chemistry for us to represent what is happening in a reaction.
The first, and simplest way of reprenting a chemical reaction is to do it in words the following shows the reaction when magnesium is burned, producing a bright blue light.
magnesium + oxygen magnesium oxide
However, in Chemistry chemical symbols are used to abbreviate the equation, these can be found on a periodic table. There is a small 2, after the O since there are two oxygen molecules bonded.
Mg + O2 MgO
The next step is to balance the equation so there are the same number of molecules on both sides. We need to double the Mg, so that one goes to each of the oxygen and that makes 2 of the product.
2Mg + O2 2MgO
Finally we add on state symbols to show what state each chemical is in when it is reacted. An (s) stands for solid; (l) for liquid; and (g) for gas. The fourth state symbol is (aq), this stands for aqueous and means the substance is dissolved.
2Mg(s) + O2(g) 2MgO(s)
Calculations
Using the the wealth of information that is packed into a chemical equation you can do some calculations, or even vice versa: do some calcualtions to get a chemical equation. I will start with the former.
Using the relative atomic masses (RAMs) and relative formula masses (RFMs) you can work out what amount of a certain substance you can get. Say you wanted to know how much hydrogen you would get when reacting 28g of lithium with water. The full balanced equation for this reaction is:
2Li(s) + 2H2O(l) 2LiOH(aq) + H2(g)
Now we will look at finding out the formula of a reaction using the results from an experiment. 4.14g of lead combines with
0.64g of oxygen.