posted by kellie on .
Solid magnesium metal reacts with chlorine gas according to the following equation:
Mg + Cl2 --> MgCl2
What mass of magnesium chloride is formed in the reaction between 7 g of Mg and 13.2 g of Cl2
is this correct
7 g+13.2 g = 20.2 grams ?
No. This is a limiting reagent problem. You know that because the problem gives BOTH the reactants.
Convert 7 g Mg to moles. Moles = grams/molar mass
Convert 13.2 g Cl2 to moles.
Convert moles Mg to moles MgCl2.
Convert moles Cl2 to moles MgClw.
It is likely that the number of moles calculated each way will not be the same which means one of them is wrong. In limiting reagent problems, the smaller answer is ALWAYS the correct one and the reactant producing that value is the limiting reagent.
Take the smaller value and convert moles MgCl2 to grams. g = moles x molar mass.