Making+as+Much+as+we+Want

a lot of things that we use in the world are made using chemical reactions this can include: So for this they work out exactly how mcuh they need to get the best reaction out of what they have. These are never quite acurrate becuase these assume that you will have 100% yeild but you might not. to work out % yeild you need to: amount of product prduced/Maximum amout of product possible X 100 very few have a 100% yeild because
 * 1) the food you eat
 * 2) ink in pens/printers
 * 3) and mmany other things.
 * the reaction may be reversiable
 * some may give unexpected results
 * some product may be left behind
 * may not completly pure.