Chem ch 16

Mixture

Combination of 2 or more kinds of matter, where each retains its own composition and properties

Homogeneous

Mixture with uniform composition (like salt water)

Heterogeneous

Mixture without uniform composition (like dirty water)

Solution

A homogeneous mixture in a single phase

Properties of solutions

1. uniform distribution of particles

2. will not settle out

3. transparent

4. can’t be filtered out (small particle size)

solute

the part that gets dissolved (typically lesser amount)

solvent

the part that does the dissolving (typically the greater amount)

Aqueous (aq)

solution that contains water as the solvent

Tinctures

solutions that contain alcohol as the solvent

Electrolyte

Anything that dissolves in water and conducts electricity (charged ions)

Suspensions

Heterogeneous mixture of the largest particles that do settle out (muddy water, pepto bismol, antacids)

Colloids

Contain intermediate size particles that remain in suspension because the DO NOT settle out (mayonnaise, foam, smoke, fog)

Degree of solubility

The amount of substance required to form a saturated solution in a certain amount of solvent at a certain temperature

3 ways to help dissolving occur

Crushing, stirring, heating

Ionic subtances dissolve in polar substances

salt in water

nonpolar substances dissolve in nonpolar substances

oil and gasoline

Immiscible substances

do not dissolve in each other (oil and vinegar in salad dressing)

Miscible substances

do not dissolve in each other in any proportion (alcohol and water)

For solids-Solubility increases as

temperature increases

For gases- solubility decreases as

temperature increases

gases only- as pressure increases

solubility increases

Henry’s law

solubility is proportional to pressure

Effervescence

the escape of a gas from a solution (like a soda bottle)

Steps for Solubility and energy changes when creating a solution

1. Breakup the solute (endothermic)

2. Breakup the solvent (Endothermic)

3. Formation of the solution (exothermic)

Heat of solution

the amt of heat absorbed or released when a solute dissolves in a solvent (heat of steps 1, 2, 3)

Heat of hydration

energy released when ions are surrounded by water molecules (heat of only step 3)

As the size of the ion decreases…

increased heat released

As the charge of the ion increases…

increased heat released

Dissociation

separation of ions caused by the action of the solvent (process of steps 1 and 2)

Hydration

The process of the solute particles being surrounded by water molecules (process of step 3)

O2 and CO2 are __________ so they…

nonpolar, dont dissolve much in water

soluble

more than one gram of solute dissolves per 100g of water

slightly soluble

between 0.1 and 1 g dissolves

insoluble

less than 0.1 g dissolves

Saturated

the solution dissolves as much solute as it can at a given temperature and a certain amount of solvent

unsaturated

the solution is currently dissolving less than the maximum amount of solute that can be dissolved at a given temperature

saturated with undissolved particles

the solution dissolves as much solute as it can at a given temperature and certain amount of solvent AND some particles are undissolved at the bottom of the container

supersaturated

the solution currently holds more than the maximum amount of solute at a given temperature (ex- sodium acetate and sodium thiosulfate)

In a solubility graph, points on the line are

saturated

In a solubility graph, points under the line are

unsaturated

In a solubility graph, points above the line are

saturated with undissolved particles

dilute

a small amount of solute in a large amount of solvent

concentrated

a larger amount of solute in a smaller amount of solvent

% solute in a solution general formula and three types

%=(solute/solution)100 OR %=(solute/solute + solvent) 100

weight/weight (chem industry)

weight/volume (medical IV)

volume/volume (alcohol solutions)

Molarity formula and what is it used for

M= moles solute/ liters of solution

used to calculate concentration

Molality formula and what its used for

m= moles solute/ kg of solvent

used to calculate concentration

Dilution Formulas (two of them)

CoVo = CnVn OR MoVo=MnVn

C=concentration

M= MOLARITY

What dissociates?

ionic compounds, and acids ionize (dissociation of a covalent compound)

What substances do not dissociate

Substances that are not acids, bases, or salts

When solutes dissolve in liquids…

they lower the freezing point

What two factors affect the degree of change in temp?

amount of solute and nature of the solvent

Colligative properties

A property that depends on the concentration (ex- freezing and boiling point)

freezing point formula

change in Tf= kf(m)(x) in water, kf=- 1.86 degrees m= molality

as the number of solute particles increases…

the freezing point decreases

boiling point formula

change in Tb= Kb(m)(x) in water,Kb= 0.512 degrees m= molality

more solute= ______ vapor pressure

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