Question

for mass - mass calculation, why is it necessary to convert the grams of starting material to moles of starting material, then determine the moles of product from the moles of starting material, and convert the moles of product to grams of product? why cant you calculate the grams of product directly from the grams of starting material? equations are written in terms of i, not. etextbook and media

Explanation:

Chemical equations show mole - to - mole ratios. Grams are a mass unit, and different substances have different molar masses. So, to use the stoichiometric ratios from the equation, we need to convert grams to moles (since the equation is in moles). We can't calculate grams of product directly from grams of starting material because the relationship between reactants and products in a chemical equation is based on mole amounts, not mass amounts (unless molar masses are the same, which is rare).

Answer:

Equations are written in terms of \(moles\), not \(grams\).