If you have 5 grams of product after a chemical reaction, how many grams of reactants did you have at the start of the reaction? question 21 options: 3 4 2 5

Iknow the answer is a but i don't know why

What is the molecular formula for a compound that is 46.16% carbon, 5.16% hydrogen, and 48.68% fluorine? the molar mass of the compound is 156.12 g/mol

Which of the following is true for the actual yield of a reaction? it is always calculated as a ratio. it is the yield from the excess reactant. it is the yield from the limiting reactant. it is always less than the theoretical yield.