SolutionsMOLAR CONCENTRATION AND TITRATIONS

Concentration

Amount of a material dissolved per unit of volume.Molar concentration: number of moles dissolved in one dm3 (L)- unit written as mol dm-3

Concentration

Also known as molarity 5.00 “molar”, or 5 M, solution of salt water is 5 times more concentrated, or saltier, than a 1.00 M NaCl solution.

Molarity (M) = moles solute

1 Liter solution

A 1.00 M NaCl solution would contain 1 mole, or 58.5 g, NaCl in 1 dm-3 of solution.

If you place 100. g NaCl in a beaker and add enough water to bring the solution to 1500 cm3, what would the molar concentration be?M= mol L

100. g NaCl 1 mol NaCl = 1.71 mol NaCl 58.5 g NaCl 1500 cm3 soln. 1 L soln = 1.500 L

soln. 1000 cm3

M= 1.71 mol NaCl = 1.1396 mol dm-3 NaCl 1.500 dm3

If you know that a 0.5 M NaCl solution will provide enough electrolytes to light a lightbulb, how many grams of salt would you need to make 1 L of this solution?1 L 0.5 mol 58.5 g = 29.25 g

NaCl 1 L 1 mol

You are working in a lab for the summer and you are asked to make a 1 M glucose (C6H12O6) solution. If you have 1 kg of glucose, how many liters of solution can you make?

Is this the amount of water you would add to the glucose?

1 kg 1000g 1 mol 1 L = 5.55 L 1 kg 180.18 1 mol

NO- the total solution will be 5.55 L but some of that volume will be taken up by the glucose. The rest will be the water.

How many moles of KI are present in 0.250 L of a 2.30 M solution?

0.250 L 2.3 mol = 0.575 mol KI 1 L

What is the formula for molarity?

How many moles of KCl are needed to make 2 liters of a 3 M KCl solution.

How many grams of KCl would that be?