MolarityMolarity

ICS IIIICS III

Week 7Week 7

Kool AidKool Aid

•Ingredients in Kool Aid

•Water

•Sugar

Kool AidKool Aid

Kool Aid is a solutionKool Aid is a solution– Mixture of solutes dissolved in solventsMixture of solutes dissolved in solvents– SoluteSolute

Dissolved particles in a solutionDissolved particles in a solution sugarsugar

– SolventSolvent The dissolving medium of a solutionThe dissolving medium of a solution waterwater

Grams per LiterGrams per Liter

represent the mass of solute divided represent the mass of solute divided by the volume of solution by the volume of solution – 50g sugar/ 100 g water50g sugar/ 100 g water

The ratio would be 1:2The ratio would be 1:2– 1 part sugar to 2 parts water1 part sugar to 2 parts water

MolarityMolarity

moles of solute divided by liters of moles of solute divided by liters of solution. solution.

Calculate the number of moles of Calculate the number of moles of dissolved solute and divide by the dissolved solute and divide by the volume in liters of the total solution, volume in liters of the total solution, yielding units of moles per liter. yielding units of moles per liter.

Grams per liter

Moles per liter

Grams of solute

Liters of solvent

moles of solute

Liters of solvent

g/L MMolarityGrams per

liter

180 g C6H12O6

1 L H2O= 180 g/L

1 mol C6H12O6

1 L H2O= 1M solution

180 g C6H12O6

= 1 mol C6H12O6

Molarity of Pepsi ColaMolarity of Pepsi Cola

12 fl oz = 355 ml = .335 12 fl oz = 355 ml = .335 LL

What is the g/L??What is the g/L??– 41g/.335 L = 122 g/L41g/.335 L = 122 g/L

What is the MolarityWhat is the Molarity– 1 mole = 180 g sugar1 mole = 180 g sugar– 41 g = .23 mol sugar41 g = .23 mol sugar

.23 mol sugar.23 mol sugar

.335 L Water.335 L Water

= .69 M= .69 M

1. How many moles of HNO3 are needed to prepare 5.0 liters of a 2.0 M solution of HNO3?

a) 2.5b) 5c) 10d) 15

5.0 liters

2.0 M

=X moles

Parts Per Million (ppm)Parts Per Million (ppm)

a ratio of one part of solute to one million a ratio of one part of solute to one million parts of solvent, is usually applied to very parts of solvent, is usually applied to very dilute solutions. dilute solutions. – Chorine in a poolChorine in a pool– 7.2 – 7.4 ppm7.2 – 7.4 ppm

To calculate parts per million To calculate parts per million – determine the mass of solvent and solutedetermine the mass of solvent and solute– divide the mass of the solute by the total mass divide the mass of the solute by the total mass

of the solution. of the solution. – Multiply by 10Multiply by 1066 (1 million) and expressed as (1 million) and expressed as

parts per million (ppm).parts per million (ppm).

Practice Problem/ ppmPractice Problem/ ppm The Dead Sea is the saltiest sea in

the world. It contains 332 grams of salt per 1000 grams of water. What is the concentration in parts per million (ppm)?

a)a) .332 ppm.332 ppm

b)b) 332 ppm332 ppm

c)c) 33,200 ppm33,200 ppm

d)d) 332,000 ppm332,000 ppm

Grams solute

Grams solvent

332 g

1000 g

= 332

X 106

332,000

Percent CompositionPercent Composition

The ratio of one part of solvent to one The ratio of one part of solvent to one hundred parts of solvent and is hundred parts of solvent and is expressed as a percent. expressed as a percent.

To calculate percent composition To calculate percent composition – determine the mass of solvent and solutedetermine the mass of solvent and solute– divide the mass of the solute by the total divide the mass of the solute by the total

mass of the solution. mass of the solution. – Multiply by 100 and expressed as a Multiply by 100 and expressed as a

percent.percent.

Percent CompositionPercent Composition The Dead Sea is the saltiest sea in

the world. It contains 332 grams of salt per 1000 grams of water. What is the percent composition?

a)a) .0332%.0332%

b)b) .332%.332%

c)c) 33.2%33.2%

d)d) 332%332%

Grams solute

Grams solvent

332 g

1000 g

= 332

X 100

33 2

Combine Both ConceptsCombine Both Concepts

What is the concentration of a 4% solution converted to parts per million (ppm)

a)a) 4,000 ppm4,000 ppm

b)b) 40,000 ppm40,000 ppm

c)c) 400,000 ppm400,000 ppm

d)d) 4,000,000 ppm4,000,000 ppm

•Step 1: Convert from percent to concentration

•4%/100

•.04

•.04 x 106 (1,000,000)