For the chemical reaction 2 HCl + Ca ( OH ) 2 ⟶ CaCl 2 + 2 H 2 O how many moles of calcium chloride (CaCl2) are produced from 2.0 mol of hydrochloric acid (HCl)

Answer 1

Coefficient represents the number of moles of each ingredient in the chemical equation. This is the number on the left hand side of the ingredient. In this case HCl has 2 to its left and CaCl₂ has nothing (which means 1, not 0). So for 2 moles of HCl, 1 mole of CaCl₂ is produced.

I hope that helps.

Mr. A

Answer 2

To solve these types of problems, you need to look at the balanced equation and pay attention to the MOLE RATIOS, i.e. the STOICHIOMETRY.

2HCl + Ca(OH)₂ ==> CaCl₂ + 2H₂O

Here the mole ratio of HCl to CaCl₂ is 2:1, or put another way, it takes TWO moles of HCl to produce ONE mole of CaCl₂. Now, we can use dimensional analysis to find the moles of CaCl₂ from 2.0 mol HCl (or you could do it in your head)...

2.0 mol HCl x 1 mol CaCl₂/2 mol HCl = 1 mole CaCl₂ produced