given the equation Mg +2HCL --> MgCL2+H2, how many moles of hydrochloric acid are needed to react with O.50 mol of magnesium ?

Question

(1)0.5
(2)1.0
(3)2.0
(4)4.0

is it 3 ?

Answer 1

It helps us help you if you don't change your screen name, especially when asking the same type question. Look back at the problem I worked with the NH3 and O2 problem? This one would be
??moles HCl = moles Mg x (moles HCl/moles Mg) = 0.50 mole Mg x (2 mol HCl/1 mol Mg) = ??. Is that 3?
Note again: You want the answer to be in units of HCl; therefore, note the mols Mg cancel and leaves units of HCl.