Chem 20: Unit 3: Solutions

gr 11

most chemical reactions occur in a ___ environment, including all chemical reactions necessary for life, therefore it’s vital to understand the physical and chemical properties of _____ solutions.

-water

-aqueous

Solutions

a homogenous mixture that has a uniform composition and the different components making up the mixture are not visible.

what is a solution composed of

at least one solute and solvent

Solute

the substance that is dissolved

Solvent

substance used to dissolve; present in the greatest quantity

usually water (which is the universal solvent)

Aqueous solution

any solution that has water as the solvent. they all have the (aq) symbol.

the solubility of ionic compounds (including bases) can be predicted…

from the solubility chart (in data booklet)

Solubility define

types on the chart explain meaning 2

the amount of solute that can be dissolved in a quantity of solvent. some compounds dissolve better than others.

**

very soluble= high solubility= state of matter (aq)

slightly soluble= low solubility= state of matter (s)

“very soluble” (solubility and state)

-high solubility

-state of matter (aq)

“slightly soluble” (solubility and state)

-low solubility

-state of matter (s)

How to use the solubility chart

1. Locate the anion at the top of the chart

2. Decide which row (top or bottom) the cation is located in. Be cautious of transition metals, make sure you’ve located the correct subscript.

3. Top row will give you high solubility (aq)

4. bottom row will give you low solubility (s)

what will always be very soluble (aq): trends on solubility chart

-all group one ions (except LiF_(s))

-All compounds containing:

• NH₄

• NO₃

• ClO₃

• ClO₄

what will always have a low solubility (s): trends on solubility chart

-elements

the ____ of a solution is related to the type of compound dissolved

-conductivity

electrolyte

-an aqueous solution that conducts electricity because it has ions, and are:

• acids

• ionic hydroxides

• highly soluble ionic compounds

***must first look at the ionic’s solubility! very soluble will have electrolytes, but slightly soluble (s) WILL NOT

non-electrolyte

-on aqueous solution that does not conduct electricity, and are mostly

• molecular compounds (except acids)

• elements

• non-soluble ionic compounds

diagnostic test for conductivity

conductivity can be tested with a conductivity metre, which will tell us if its an electrolyte (light goes on) or if its a non-electrolyte (light dosen’t turn on)

Litmus Test: Acidic solutions:

tyoes/whats it

blue litmus turns red.

• Hydrogen containing compounds: Hydrogen on the left of a chemical formula or COOH is written within the formula

Litmus Test: Basic/Alkaline solutions:

what is it

red litmus turns blue

• ionic hydroxides, has OH_^-

diagnostic test for acidity

is done using litmus paper. red=acid, blue=base, no change on both=neutral

Litmus Test: Neutral solutions:

what will be neutral always

no change in the colour of the litmus paper

• ionic compounds

• molecular compounds

Diagnostic Tests

-are used to determine properties of a solution or to identify a particular substance:

• Conductivity = electrolytes

• Litmus = acid/base

• flame = elements

• solution colour = Ions

Qualitative Analysis

-examines the properties of substances

diagnostic tests does this

Arrhenius’ Theory: Electrolyte

-disperse charged particles throughout the solution

-when a compound dissolves in water, existing ions are separated as individual aqueous ions. Positive ions are surrounded by the negative ends of the polar water molecules, while negative ions are surrounded by the positive ends of polar water molecules.

• ionic compounds (soluble)

• acids

• bases

Arrhenius’ Theory: Non-Electrolyte

-disperse electrically neutral particles throughout the solution.

-when dissolving, molecules of the compound separate from each other and disperse in an aqueous solution as individual molecules are surrounded by water molecules.

• molecular compounds

• elements

• insoluble ionic (Stays at the bottom as a clumped, charged ionic solid crystal lattice. Will form a solid precipitate of the ionic compound and WILL NOT DISPERSE.)

Arrhenius’ theory

He proposed that:

• when a substance dissolves, particles of that substance separate from each other and disperse into the solution. This determines whether a solution is an electrolyte or non electrolyte.

Dissociation

-the separation of ions that occurs when an ionic compound dissolves in water

Dissociation equations

balanced equations used to show the separation of ions in a solution:

• the formula of the solvent, H₂O does not appear as a reactant, and is rather indicated by the (aq).

• so you first write the formula, then arrows dividing into its ions as the specific type dictates.

Major Entity:

the chemicals or ions that is mostly present in the solution

Soluble Ionic Compounds:

-define

-equation

-major entities

-dissociate into aqueous ions and can be shown using a dissociation equation.

-will form a dissociation equation

-major entities: cation_(aq), anion_(aq), H₂O_(l)

Insoluble Ionic Compounds:

-define

-equation

-major entities

-remain solid compounds and have no dissociation

-NO EQUATION

-major entities: compound_(s), H₂O_(l)

name all dissociation

bases, ionic compounds (soluble and insoluble(no equation))

name all ionization

acids (weak and strong), molecular compounds and elements (no equation)

basic/alkaline compounds:

-define

-equation

-major entities

-are ionic hydroxide compounds that dissociate into individual positive ions and negative hydroxide ions in a solution. treat them just like ionic so make sure you first check their solubility so you know if you have to treat them as soluble or insoluble.

-major entities: cation_(aq), OH^-_(aq), H₂O_(l), or compound_(s) (for insoluble)

-will have dissociation equation if soluble(aq). if insoluble(s) will not have equation.

Ionization

-process by which a neutral atom or molecule is converted into an ion.

• acids are molecular compounds that will form ions, as their properties appear only when compounds containing hydrogen dissolve in water

• all acids have an ionization equation, but ionize to different degrees

Strong Acids

-define

-equation

-major entities

-have a high degree of ionization (~100%) and are good conductors.

-do have ionization equation, ions will seperate

-major entities: H⁺_(aq), anion, H₂O_(l)

6 common strong acids

• Hydrochloric acid (HCl)

• Hydrobromic acid (HBr)

• Hydroiodic acid (HI)

• Sulfuric acid (H₂SO₄)

• Nitric acid (HNO₃)

• Perchloric acid (HClO₄)

Weak Acids

-define

-equation

-major entities

-have a low degree of ionization and are poor conductors

-will keep full compound in ionization equation

-major entities: acid_(aq), H₂O_(l)

Molecular Compounds/Elements

-define

-equation

-major entities

-do not dissociate in water and have no dissociation equation.

-will have no ionization equation

-major entities: molecule_(aq)/element_{(s, l, or g)}, H₂O_(l)

_{(for state of molecule: nonpolar=symetrical= own state. then polar=unsymetrical= aq)}