Calculate the theoretical yield in moles of magnesium chloride when 37 grams of Mg(s) react with 38 grams of HCl(aq).Write the answer using 2 decimal places and do not use scientific notation.

The correct answer is 0.52 moles.

Explanation:

Based on the given question, 37 grams of magnesium reacts with 38 grams of HCl to produce MgCl2 or magnesium chloride. The reaction is:  

Mg (s) + 2HCl (aq) ⇒ MgCl2 (aq) + H2 (g)

There is a need to find the theoretical yield in moles of MgCl2. The formula for calculating the no. or moles is mass/molar mass. Therefore, moles of magnesium is 37/24 = 1.54 and moles of HCl will be 38/36.5 = 1.04.  

From the reaction it is clear that one mole of magnesium reacts with two moles of HCl, as lesser quantity of HCl is present in the given case, therefore, HCl will be the limiting reagent.

Now theoretical moles of magnesium chloride will be,  

= moles of HCl / 2

= 1.04 / 2  

= 0.52 moles

c. 4.54 x 10–12 j happens to be correct