Calculate Molarity Video Lessons

Concept:

# Problem: Hydrochloric acid is usually purchased in a concentrated form that is 37.0% HCl by mass and has a density of 1.20 g/mL.How much concentrated solution would you take to prepare 2.90 L of 0.505 M HCl by mixing with water?

###### FREE Expert Solution

We’re being asked to calculate the volume of concentrated HCl needed to prepare a 2.90 L of 0.505 M HCl.

Recall that molarity is the ratio of the moles of solute and the volume of solution (in liters)

In other words:

We’re given the mass percent of concentrated HCl which is 37.0%.

Recall that mass percent is given by:

This means in 100 g of solution, we have 37 g HCl

The steps we need to do for this solution are:

Step 1: Calculate the moles of HCl

Step 2: Calculate the volume of the solution (in L).

Step 3: Calculate the molarity of the solution.

Step 4: Calculate the volume of solution needed (in L) using dilution equation.

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###### Problem Details

Hydrochloric acid is usually purchased in a concentrated form that is 37.0% HCl by mass and has a density of 1.20 g/mL.

How much concentrated solution would you take to prepare 2.90 L of 0.505 M HCl by mixing with water?