10. The density of 2M solution of sodium chloride (NaCl) 1.13 g mol/litre.
Calculate molarity of the solution. M = 2 mol per litre.
Answers
Step-by-step explanation:
To get the molarity, you divide the moles of solute by the litres of solution.
Molarity
=
moles of solute
litres of solution
For example, a 0.25 mol/L NaOH solution contains 0.25 mol of sodium hydroxide in every litre of solution.
To calculate the molarity of a solution, you need to know the number of moles of solute and the total volume of the solution.
To calculate molarity:
Calculate the number of moles of solute present.
Calculate the number of litres of solution present.
Divide the number of moles of solute by the number of litres of solution.
EXAMPLE:
What is the molarity of a solution prepared by dissolving 15.0 g of NaOH in enough water to make a total of 225 mL of solution?
Solution:
1 mol of NaOH has a mass of 40.00 g, so
Moles of NaOH
=
15.0
g NaOH
×
1 mol NaOH
40.00
g NaOH
=
0.375 mol NaOH
Litres of solution
=
225
mL soln
×
1 L soln
1000
mL soln
=
0.225 L soln
Molarity
=
moles of solute
litres of solution
=
0.375 mol
0.225 L
=
1.67 mol/L
Some students prefer to use a "molarity triangle".
labscience10ablock.wikispaces.com
It summarizes the molarity formulas as
Moles
=
molarity × litres
Molarity
=
moles
litres
Litres
=
moles
molarity