Question

Which conversion factor should be used to solve the following problem?

How many moles of water (H2O) would be produced from the reaction of 3.25 moles of hydrochloric acid (HCl) reacting with excess calcium hydroxide Ca(OH)2?

Ca(OH)2 +2HCl --> CaCl2 + 2H2O

3.25 mol HCL x ?
Question 2 options:


2 mol HCl / 2 mol H2O


2 mol H2O / 2 mol HCl


2 mol HCl / 1 mol CaCl2


1 mol CaCl2 / 2 mol HCl

Answer 1

2 moles of H₂O / 2 moles of HCl.

Step-by-step explanation:

The balanced equation for the reaction is given below:

Ca(OH)₂ + 2HCl —> CaCl₂ + 2H₂O

From the balanced equation above,

2 moles of HCl reacted to produce 2 moles of H₂O.

Next, we shall determine number of mole of H₂O produced by the reaction of 3.25 moles of HCl. This can be obtained as follow:

From the balanced equation above,

2 moles of HCl reacted to produce 2 moles of H₂O.

Therefore, 3.25 moles of HCl will react to produce = 3.25 moles of HCl × 2 moles of H₂O / 2 moles of HCl.

Thus, the conversion scale is:

3.25 moles of HCl × 2 moles of H₂O / 2 moles of HCl.