Molarity is the most common solution concentration in calculations dealing with volumetric stoichiometry. The units of molarity,

**Molarity (M)** is defined as moles of solute per
liter of solution. The formula for molarity is:

We are asked to make a 3M solution of NaCl in 1000 mL (1 liter) of water.

**Step 1: Calculate moles of NaCl needed**

- Molarity (M) = 3 M (mol/L)
- Volume of solution (V) = 1000 mL = 1 L
- Moles of NaCl = Molarity × Volume

**Step 2: Convert moles to grams**

- The molar mass of NaCl (sodium chloride) is 58.44 g/mol.

**Step 3: Procedure for preparing the solution**

- Weigh 175.32 g of NaCl.
- Dissolve it in a small amount of distilled water.
- Transfer the solution into a 1000 mL volumetric flask.
- Add distilled water until the total volume reaches 1000 mL.

**Calculation using the CHEMIX School Concentration
and Dilution Calculator**

**1.)** Select
Sodium chloride from the compound drop down menu.

**2.)** Insert 3 in the Molar (M)
concentration field.

**3.)** Insert 1000 in the V_{Solution} -field

**CHEMIX School Answer
(Solution preparation procedure)****:**

To prepare 1000mL of a 3
Molar sodium chloride solution:

******************************* By volume:
*******************************

Put about 400

mL of water into a flask and add 175.327g of pure sodium chloride.
Add water until 1000mL.

******************************** By mass:
********************************

Put about 400g of water into a flask and add 175.327g of pure
sodium chloride. Add water until 1114.16g.

**Fig. **Concentration Calculator -
Molarity Calculation Example - Screenshot from CHEMIX School

The dilution formula is:

$M_1V_1 = M_2$Where:

- $M_1$ = initial molarity (stock concentration) = 5M
- $V_1$ = volume of stock solution to use
- $M_2$ = final molarity = 3M
- $V_2$ = final volume = 500 mL = 0.5 L

**Step 1: Solve for $V_1$**

**Step 2: Procedure - Dilution**

- Measure 300 mL of the 5M NaCl stock solution.
- Add enough distilled water to bring the total volume to 500 mL.
- Mix thoroughly.

**Calculation using the CHEMIX
School Concentration and Dilution Calculator**

**1.)** Select Sodium chloride from the compound drop down
menu.

**2.)** Insert 3 in the Molar (M) concentration field.

**3.)** Insert 500 in the V_{Solution} -field

**4.)** Insert 5 and select Molar in the Stock concentration
fields

**CHEMIX School Answer (Dilution - Solution preparation
procedure):**

To prepare 500mL of a 3 Molar sodium chloride solution:

************ Dilution by volume ************

Put about 100mL of water into a flask and add 300mL sodium
chloride stock conc. Add water until 500mL

************ Dilution by mass ************

Put about 100g of water into a flask and add 355.726g of sodium
chloride stock conc. Add water until 557.081g

**Fig. **Dilution Calculator - *Molarity
Calculation Example *- Screenshot from CHEMIX
School

Concentration
and Dilution Calculator User Manual

Molality
Calculator