Now that we understand the mole concept and mol-mol conversion factors, we're ready to do quantitative calculations. Consider the rusting of oxygen:
Method 2: Steps 1-3 above can be accomplished in one overall calculation by treating the problem like a dimensional analysis problem:
The second method is somewhat easier since it can be accomplished in one line. Let us do one more example:
Consider the combustion of butane:
If we need to recover 150 g of water, what mass of butane is necessary? The method 2 result is:
Most chemical calculations involving masses are carried out in a similar manner.