Solutions: DefinitionsSolutions: Definitions

Solution - Solution - homogeneous mixturehomogeneous mixture

Solvent Solvent - present in - present in greater amountgreater amount

Solute Solute - substance - substance being dissolvedbeing dissolved

SolutionsSolutions

What the solute and the solvent are What the solute and the solvent are determinesdetermines

whether a substance will dissolve. whether a substance will dissolve. how much will dissolve.how much will dissolve.

Types of SolutionsTypes of Solutions

Solute Solvent Solution

Gaseous Solutions

gasliquid

gasgas

air (nitrogen, oxygen, argon gases)humid air (water vapor in air)

Liquid Solutions

gasliquidsolid

liquidliquidliquid

carbonated drinks(CO2 in water)vinegar (HC2H3O2 in water)salt water (NaCl in water)

Solid Solutions

liquidsolid

solidsolid

dental amalgam (Hg in Ag)sterling silver (Cu in Ag)

Charles H.Corwin, Introductory Chemistry 2005, page 369

Classes of SolutionsClasses of Solutionsaqueous solution:

water = “the universal solvent”

solvent = water

amalgam: solvent = Hg

e.g., dental amalgam

tincture: solvent = alcohol

e.g., tincture of iodine (for cuts)

organic solution: solvent contains carbon

e.g., gasoline, benzene, toluene, hexane

Non-Solution DefinitionsNon-Solution Definitions

insoluble: “will NOT dissolve in”

e.g., sand and water

immiscible: refers to two gases or two liquids that will NOT form a solution

e.g., water and oil

suspension: appears uniform while being stirred, but settles over time

SolvationSolvation

Solvation – Solvation – the process of dissolvingthe process of dissolving

solute particles are separated and solute particles are separated and pulled into solutionpulled into solution

solute particles are surrounded by solute particles are surrounded by solvent particlessolvent particles

Na+

Na+

Na+Cl-

Cl-Cl-

NaCl solid

salt

NaCl (aq) = Na+ = Cl-

Dissolving of solid NaClDissolving of solid NaCl

Solution, Suspension, ColloidSolution, Suspension, Colloid

Timberlake, Chemistry 7th Edition, page 309

The main difference is PARTICLE SIZE.

•Solution: the particles are very small and are dissolved between the molecules of the solvent

•Colloid: the particles are still small enough to fit in the interstitial spaces, but large enough to be seen with the naked eye.

Both a solution and a colloid are homogeneous mixtures.

•Suspension: the particles are not dissolved in the solution, too large to fit in the interstitial spaces - they are stirred up and suspended in the solvent for short periods of time.

Suspensions settle out when allowed to stand undisturbed.

SolubilitySolubility

Water

HOT

A B A B

AFTERBefore

Water

COLD

Water

HOT

Add 1 drop of red food coloring

Miscible – “mixable”

two gases or two liquids that mix evenly

Experiment 1:

Water

COLD

SolubilitySolubility

Water Water

Oil

T0 sec T30 sec

AFTER

Before

Add oil to water and shake

Immiscible – “does not mix”

two liquids or two gases that DO NOT MIX

Experiment 2:

Muddy Water: Dissolved SolidsMuddy Water: Dissolved Solids

Muddy

Water

T1 min T5 min

AFTER

Water

Before

Add soil to water, shake well, and allow to settle

Dissolved solids can be calculatedas a percentage:

v/v (volume/volume)w/v (weight/volume)w/w (weight/weight)

5 mL solid / 95 mL water

5% v/v soil in water

5 mL / 100 mL = 5%

CentrifugationCentrifugation

Spin sample very rapidly: Spin sample very rapidly: denser materials go to denser materials go to bottom (outside)bottom (outside)

Separate blood into Separate blood into serum and plasmaserum and plasma Serum (clear)Serum (clear) Plasma (contains red Plasma (contains red

blood cells ‘RBCs’)blood cells ‘RBCs’)• Check for anemia (lack of Check for anemia (lack of

iron)iron)

Blood

RBC’s

Serum

A B C

AFTER

Before

Making a Making a Dilute Dilute

SolutionSolutionTimberlake, Chemistry 7th Edition, page 344

initial solution

removesample

diluted solution

same number ofmoles of solutein a larger volume

mix

moles ofsolute

Glassware – Precision and CostGlassware – Precision and Costbeaker vs. volumetric flask

When filled to 1000 mL line, how much liquid is present?

beaker volumetric flask5% of 1000 mL = 50 mL 1000 mL + 0.30 mL

Range: 950 mL – 1050 mL Range: 999.70 mL– 1000.30 mLimprecise; cheap precise; expensive

~ ~ ~ ~ ~ ~ ~ ~

water ingrad. cyl.

mercury ingrad. cyl.

Measure to part of meniscus w/zero slope.

Dilution of SolutionsDilution of Solutions

Solution GuideSolution GuideFormulaFormula

WeightWeightSpecific Specific GravityGravity MolarityMolarity

ReagentReagent

PercentPercent

To Prepare 1To Prepare 1

Liter of one molarLiter of one molar

SolutionSolution

Acetic Acid Glacial (CHAcetic Acid Glacial (CH33COOH)COOH) 60.0560.05 1.051.05 17.4517.45 99.8%99.8% 57.3 mL57.3 mL

Ammonium Hydroxide (NHAmmonium Hydroxide (NH44OH)OH) 35.0535.05 0.900.90 14.5314.53 56.6%56.6% 69.0 mL69.0 mL

Formic Acid (HCOOH)Formic Acid (HCOOH) 46.0346.03 1.201.20 23.623.6 90.5%90.5% 42.5 mL42.5 mL

Hydrochloric Acid (HCl)Hydrochloric Acid (HCl) 36.4636.46 1.191.19 12.112.1 37.2%37.2% 82.5 mL82.5 mL

Hydrofluoric Acid (HF)Hydrofluoric Acid (HF) 20.020.0 1.181.18 28.928.9 49.0%49.0% 34.5 mL34.5 mL

Nitric Acid (HNONitric Acid (HNO33)) 63.0163.01 1.421.42 15.915.9 70.0%70.0% 63.0 mL63.0 mL

Perchloric Acid 60% (HClOPerchloric Acid 60% (HClO44)) 100.47100.47 1.541.54 9.19.1 60.0%60.0% 110 mL110 mL

Perchloric Acid 70% (HClOPerchloric Acid 70% (HClO44)) 100.47100.47 1.671.67 11.711.7 70.5%70.5% 85.5 mL85.5 mL

Phosphoric Acid (HPhosphoric Acid (H33PO4)PO4) 97.197.1 1.701.70 14.814.8 85.5%85.5% 67.5 mL67.5 mL

Potassium Hydroxide (KOH)Potassium Hydroxide (KOH) 60.0560.05 1.051.05 17.4517.45 99.8%99.8% 57.3 mL57.3 mL

Sodium Hydroxide (NaOH)Sodium Hydroxide (NaOH) 40.040.0 1.541.54 19.419.4 45.0%45.0% 85.5 mL85.5 mL

Sulfuric Acid (HSulfuric Acid (H22SOSO44)) 98.0898.08 1.841.84 18.018.0 50.5%50.5% 51.5 mL51.5 mL

MConc.VConc. = MDiluteVDilute

2211 VMVM

DilutionDilution

Preparation of a desired solution by Preparation of a desired solution by adding water to a concentrate.adding water to a concentrate.

Moles of solute remain the same.Moles of solute remain the same.

DDCC VM VM

L) (25.00 M 0.500 )(V M 14.8 VM VM C DDCC

C = concentrateD = dilute

Dilutions of Solutions Acids (and sometimes bases) are purchased in concentrated form (“concentrate”) and are easilydiluted to any desired concentration.

**Safety Tip: When diluting, add acid or base to water.**

Dilution Equation:

Concentrated H3PO4 is 14.8 M. What volume of concentrate

is required to make 25.00 L of 0.500 M H3PO4?

VC = 0.845 L = 845 mL

Be sure to wear your safety glassessafety glasses!

1. Measure out 0.845 L of concentrated H3PO4 .

2. In separate container, obtain ~20 L of cold H2O.

3. In fume hood, slowly pour [H3PO4] into cold H2O.

4. Add enough H2O until 25.00 L of solution is obtained.

How would you mix the above solution?

Preparing SolutionsPreparing Solutions

500 mL of 1.54500 mL of 1.54MM NaCl NaCl

500 mLwater

45.0 gNaCl

mass 45.0 g of NaClmass 45.0 g of NaCl add water until add water until totaltotal volume is volume is

500 mL500 mL

mass 45.0 g of NaClmass 45.0 g of NaCl add 0.500 kg of wateradd 0.500 kg of water

500 mLmark

500 mLvolumetric

flask

1.541.54molmol NaCl in NaCl in 0.500 kg of water0.500 kg of water

Preparing SolutionsPreparing Solutions

250 mL of 6.0250 mL of 6.0MM HNO HNO33

by dilutionby dilution measure 95 mL measure 95 mL

of 15.8of 15.8MM HNO HNO33

95 mL of15.8M HNO3

water for

safety

250 mL mark

combine with water until combine with water until totaltotal volume is 250 mLvolume is 250 mL

Safety:Safety: “Do as you oughtta, “Do as you oughtta, add the acid to the watta!”add the acid to the watta!”

Solution Preparation RelaySolution Preparation Relay Turn in one paper per team. Turn in one paper per team. Complete the following steps:Complete the following steps:

A) A) ShowShow the necessary calculations. the necessary calculations.

B) Write out B) Write out specificspecific directions for preparing the solution. directions for preparing the solution.

For each of the following solutions:For each of the following solutions:

1) 100.0 mL of 0.501) 100.0 mL of 0.50MM NaCl NaCl

2) 0.252) 0.25molmol NaCl in 100.0 mL of water NaCl in 100.0 mL of water

3) 100.0 mL of 3.03) 100.0 mL of 3.0MM HCl from 12.1 HCl from 12.1MM concentrate. concentrate.