CHEMISTRY COMMUNITY

This problem gives percentages anyway, but if a problem were to give me amounts in grams, could I convert to moles and find a ratio that way? Why does the book teach us to find mass percentages and then use a sample mass of 100g?

If the problem were to give you the amount in grams, you could convert it to moles and then divide by the smallest number of moles to get the ratios. The book is just showing another route to getting the answer. There are, in most cases, more than one correct way of getting the answer. Hope that helps!

Both ways are correct they only teach it that way so the concept is easier to grasp. Personally, I convert from grams to moles and just divide the smallest from there and you end up with the same thing anyways so its only a matter of preference.