Solutions & Solubility - Unit 4 Chem 11

Amalgam

Alloy of mercury and a metal (liquid dissolved in a solid - fillings)

Ionic Compound

Most ionic compounds are soluble in water

Dissociation

the separation of ions that occurs when an ionic compound dissolves. Cation is attracted to the negative dipole and vice versa

Hydration

water then surrounds each ion in this process

What has an affect on solubility?

Ionic charge and ion size. Larger solubility when ionic size is larger because far apart lower attractive force

Molecular compounds

Most polar compounds dissolve in a water because the hydrogen bonds between the solute and water are greater than the dipole-dipole attractions between the molecules

Miscible

liquids that dissolve freely in one another in any proportion. Ethanol and methanol (polar - polar) and nonpolar-nonpolar. LIKE dissolves LIKE

Immiscible

Liquids like oil and water do not mix (nonpolar-polar)

Surfactants

reduce the surface tension of a solvent, allowing polar and nonpolar substances to mix. They usually have a hydrophobic (nonpolar) and hydrophilic (polar) end Eg. soap

effects of pressure on solubility - solids and liquids

little effect, not very compressible

effects of pressure on solubility - gases

higher pressure, higher solubility

Acid Properties:

Taste: Sour, Smell: Strong burning, Reactivity: metals to form hydrogen gas, Conductivity: In water, Texture of solution: Sticky

Base Properties:

Taste: Bitter, Smell: no smell usually except NH3, Reactivity: oil and organic compound, Conductivity: resin, water Texture of solution: Slippery, slimy/soapy

Neutral Properties:

Taste: No smell to very smelly, Smell: no smell to very smelly, Reactivity: varies, Conductivity: varies, Texture of solution: oily, sticky, slippery

When are solutions called acidic, basic/alkaline, or neutral?

When they have more acid/base molecules than base/acid molecules. Called neutral if there is an equal amount of both

The Arrhenius Theory of Acids and Bases (1884)

An acid is a substance that produces H+ ions when dissolved in water. In essence we are increasing the concentration of H+ ions in solution.

A base is a substance that produces an OH- ion when dissolved in water. In essence we are increasing the concentration of OH- ions in solution. Only compounds with OH- ions can be classified as Arrhenius bases.

Disadvantages of The Arrhenius Theory:

1. It can be applied only to reactions that occur in water

2. Doesn't explain why salts are not all neutral, as Arrhenius predicts.

Bronsted-Lowry Theory of Acids and Bases (1923):

Bronsted-Lowry Acids are compounds that gives H+ ions to other compounds.

Bronsted-Lowry Bases are the compounds that accepts the H+ ions

Therefore, acid-base reactions are a hydrogen ion (proton) exchange reaction

Acids can only donate a proton if it is around a substance that can act like a base

How can Bronsted-Lowry bases be identified?

From their Lewis Structure.

The only way to accept an H+ ion is to form a covalent bond to it.

Thus, only compounds that have pairs of non-bonding valence (lone pair) electrons can act as H+ ion acceptors, or Bronsted Bases.

Conjugate Acid-Bases Pairs:

Differ in formula by one hydrogen ion. Acid in the pair donates a proton to become its conjugate base

Amphoteric

It can be either an acid or a base. Depending what it's reacting with at the time

Electrolytes:

conduct electricity in water

Electricity is conducted due to:

ions in the water.

Dissociation:

is the process of water pulling ions into solution

Strong electrolyte:

A solution in which the entire compound is present as ions

Weak electrolyte:

A solution in which a proportion of the compound is still in molecular form

Strength of the acid:

Directly related to its degree of ionization

Strength of the base:

Directly related to its degree of dissociation

Strong acid vs. weak acid

Strong ionize completely while weak ionize partially

Strong base vs. weak base

Strong dissociate completely while weak dissociate partially

Equilibrium reaction:

Indicate that a proportion of reactants still remains in solution, uses double headed arrow.

Solution

A homogeneous mixture of two or more substances

Homogeneous mixture

A mixture in which substances are evenly distributed throughout the mixture. Particles are too small to be seen. Solid, liquids, or gases

What does a solution look like

Homogeneous, do not separate on standing, do not scatter light, cannot be separated by filtration, 0.01 nm; atoms, ions, molecules

what does Colloids look like

Heterogeneous, 1-1000 nm, dispersed; large molecules or aggregates, do not seperate, cannot be seperated by filtration, scatter light

What do suspensions look like

Heterogeneous, over 1000nm, suspended; large particles or aggregates, particles settle out, can be separated by filtration, may either scatter light or be opaque

A solution contains:

one or more solute(s) and a solvent

Concentration

ratio of the amount of solute to amount of solution/solvent

Concentrated solution

large quantity of solute dissolved per unit volume

Dilute solution

small quantity of solute dissolved per unit volume

Saturated

a solution which contains the MAX amount of solute that can be dissolved in a given amount of solvent at a particular temperature

Unsaturated

A solution which contains LESS than the max amount of solute that can be dissolved

Supersaturated

A saturated solution that has been heated to dissolve EXTRA solute and then cooled to the original temperature without the reappearance of the extra solid

Aqueous Solution

a solution in which water is the solvent (aq)

Alloy

a solution of two or more metals (solid dissolved in a solid)

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