How many milliters of a 6.ooM HCl solution are required to react with 21.0 grams of Mg?
I'm so confused. I know how to get the Molar mass of Mg and HCl but, does that even matter here?
Mg + 2HCl ==> MgCl2 + H2
mols Mg = grams/atomic mass = ?
Using the coefficients in the balanced equation convert mols Mg to mols HCl. In this case mols HCl = 2 x mols Mg.
Now that you know mols HCl,
M HCl = mols HCl/L HCl. You know M and mols, solve for L and convert to mL.
Don't get confused by these things. They follow simple rules.
1. Write the equation and balance it
2. Convert what you have to mols. For solutions it is M x L = mols. For solids (mass in grams) it is mols = grams/atomic mass if atoms or grams/molar mass if compounds.
3. Convert mols of what you to mols of what you want.
4. Then convert mols of what you want to grams(g = mols x molar mass or mols x atomic mass). If you don't want grams but you want volume, then use PV = nRT OR remember that gases occupy 22.4 L for every mole at STP.