Stiochiometry Help please!

When magnesium metal and an aqueous solution of hydrochloric acid combine, they produce an aqueous solution of magnesium chloride and hydrogen gas. Using the equation, Mg (s) + 2HCl (aq) MgCl2 (aq) + H2 (g), if 72.9 g of Mg and 146.0 g of HCl are allowed to react, identify the limiting reagent.

Mg
HCl
MgCl2
H2


I am studying for my finals and need help on this question. ANy help would be appreciated and gets 10 points!!?

Solve for either 1.) how many grams of Mg is needed to react with 146.0g HCl or 2.) how many grams of HCl is require to react with 72.9g of Mg.

I am going to use option 1... 36.45g is the molar mass of HCl. According to the balanced equation 1 mole of Mg reacts with 2 moles of HCl, and 24.31g is the molar mass of Mg, so set up the stoichiometry problem like this:
? g Mg = 146.0g HCl x (1 mole HCl/36.45g HCl) x (1 mole Mg/2 moles HCl) x (24.31g Mg/1 mole Mg) = 48.69g

Now compare that with the given amount of Mg they give you, which is 72.9g. They give you more grams of Mg than you need, so Mg is the excess reagent, leaving HCl as your LR.

Remember, the limiting reagent is always a reactant-- not a product, so you can automatically eliminate MgCl2 and H2 as the answer.

there is not enough info. you need to determine whether you are dealing w moles or not