SOLUTIONSChapter 12

West Valley High SchoolGeneral Chemistry

Mr. Mata

Standard 5

Students know that temperature, pressure, and surface area affect the dissolving process.

Essential Question:

What are the components of a

solution and how do solutions,

suspensions, and colloids

differ from one another?

What is a Solution? Solution = homogeneous mixture of

two or more substances.

(solute & solvent) Solute = substance being dissolved. Solvent = substance doing the

dissolving. Homogeneous mixture = completely

dissolved & uniform solute in solvent Aqueous solution = solution in which

the solvent is water.

Parts of a Solution

Homogeneous vs. Heterogeneous

• 24-karat gold is pure gold = homogeneous

• 14-karat gold is an alloy (mixture) Au, Ag, Cu = heterogeneous• 14-karat gold is 14/24 (58.3%) gold

Solubility Terminology Soluble = substance that can be

dissolved. Insoluble = substance that cannot be

dissolved. Solubility = measure of how much

solute will dissolve in solvent. Miscible = two liquids that dissolve in

each other (ex: water & ethanol). Immiscible = two liquids that don’t

dissolve in each other (ex: H2O & oil).

Immiscible Liquids

Solubility Terminology SATURATED—contains the maximum

amount of solute. UNSATURATED—contains less solute

than a saturated solution. SUPERSATURATED—contains more

solute than it should.

Solution Saturations

Factors affecting Solubility

Stirring (agitation) increases solubility. Surface Area (particle size) smaller size

increases surface area: increases sol. Pressure (gases) increased pressure

increases gas solubility. Temperature (solids & gases).

solids: temp increase = increases solubility

gases: temp increase = decrease solubility

Solution Concentration Concentration: measure of the amount

of solute that is dissolved in a given quantity of solvent.

Dilute solution = solution that contains small amount of solute.

Concentrated solution = solution that contains a large amount of solute.

Molarity (M) = moles of solute/L of soln Units = M or moles/Liter (mol/L).

Suspensions Suspension – particles in a solvent are

so large that they settle to bottom unless agitated.

Ex: muddy water Soil particles will sink to bottom. Can be separated from heterogeneous

mixtures by filtering.

Colloids Particles are intermediate in size

between those in solutions and suspensions.

1 nanometer (nm) to 1000 nm. Cause mixture to look “cloudy”. Ex: mayonnaise Egg yolk keeps the oil droplets

dispersed.

MOLARITY

Molarity (M) = moles of solute

Liters of solution

Units in mol/L or M

A saline solution contains 0.90 g NaCl in exactly 100 mL of solution. What is the molarity of the solution?

M = moles solute Liters of solution0.90 g NaCl x 1 mol NaCl = 0.02 mol NaCl 58 g NaCl100 mL x 1 L = 0.1 L 1000 mL M = 0.02 mol = 0.2 mol/L or 0.2 M 0.1 L

M = moles solute Liters of solution

325 g CaCl2 x 1 mol CaCl2 = 2.95 mol CaCl2

110 g CaCl22500 mL x 1 L = 2.5 L 1000 mL M = 2.95 mol = 1.2 mol/L or 1.2 M 2.5 L

A solution contains 325 g CaCl2 in exactly 2500 mL of solution. What is the molarity of the solution?

How many moles of solute are present in 1.5 L of 0.24 M Na2SO4?

M = mol -> mol = ML

L

0.24 M Na2SO4 = 0.24 mol/L Na2SO4

Mol = (0.24 mol/L) (1.5L) = 0.36 mol

How many moles of solute are present in 20 L of 12 M H2SO4?

M = mol -> mol = ML

L

12 M H2SO4 = 12 mol/L H2SO4

Mol = (12 mol/L) (20L) = 240 mol

Percent SolutionsWhat is the percent by volume of ethanol in the

final solution when 85 mL of ethanol is diluted with 250 mL of water?

%v/v = volume of solute x 100

solution volume

%v/v = 85 mL ethanol x 100 =

250 mL H2O

= 34% ethanol (v/v)

Percent Solutions

What is the percent by volume of ethanol in the final solution when 300 mL of ethanol is diluted with 600 mL of water?

%v/v = volume of solute x 100

solution volume

%v/v = 300 mL ethanol x 100 =

600 mL H2O

= 50% ethanol (v/v)

Parts per Million Parts per million (ppm) Aqueous solutions: 1 ppm = 1000 ng/L

The federal limit of lead in tap water is 0.015 ppm. Express this concentration in ng/L.

0.015 ppm x 1000 ng/L = 15 ng/L

1 ppm

Parts per Million

The federal limit of mercury in tap water is 0.0002 ppm. Express this concentration in ng/L.

0.0002 ppm x 1000 ng/L = .2 ng/L

1 ppm

Chapter 12 SUTW Prompt Describe the differences between an

unsaturated, saturated, and supersaturated solution.

Complete a 10 -12 sentence paragraph using the SUTW paragraph format. Hilight using green, yellow, and pink.

Due Date: Tomorrow (start of class).