Chemistry: The Central Science Chapter 4

solution

Homogeneous mixture of two or more substances

solvent vs solute

solvent - greatest quantity

solute - smaller quantity, gets dissolved

When is a solution aqueous

the solvent is water

Is pure water conductive

no

electrolyte

A substance that creates aqueous solutions that contains ions. It dissociates into Ion in the solution

nonelectrolyte

A substance that creates aqueous solutions that does not contain ions. It does not break up into ions

which types of compounds create electrolytes/nonelectrolytes

Ionic compounds - electrolytes
molecular compounds - nonelectrolyes

dissociate

the act of a compound breaking apart into ions during the act of dissolving

Why is H2O good for dissolving (thus dissociating) ionic compounds

It's partial charges

H ions are partial positive
O ion is partial negative

solvation/ solvated state

solvation is an interaction of a solute with the solvent, which leads to stabilization of the solute species in the solution. One may also refer to the solvated state, whereby an ion in a solution is surrounded or complexed by solvent molecules

What kinds of molecular compounds dissolved into ions

acids

ionize

convert (an atom, molecule, or substance) into an ion or ions, typically by removing one or more electrons

Strong electrolytes vs weak electrolyets

strong - exist almost completely as ions in aqueous solutions. All water soluble ionic compounds, few molecular compounds

weak - exist mostly in the form of neutral molecules in aqueous solutions and only a small fraction dissociates into ions

solubility

the amount to which a substance will dissolve at a given temperature

How to write the equation for an ionizing reaction (weak electrolytes)

The two arrows mean the reaction is happening in both directions. As AH dissociates A+ and H+ recombine to become AH again.

This achieves chemical equalibrium

chemical equalibrium

number of each type of ion/molecule in a solution is constant

How to determine if a compound is an ionic compound

The presence of both metals and nonmetals

except if an ion contains NH4+

precipitation reaction

when a reaction in a liquid solution creates a solid

charged ions attract each other so strongly the create an insoluble solid

precipitate

the solid formed by the precipitation reaction.

are double displacement (metathesis) reactions redox reactions?

Not a redox reaction

double displacement reaction

1. use the chemical formulas of the reactants to figure out which ions are present

2. write the chemical formulas of the products by combining the cation from one reaction with the anion of the other. Us the charges to determine the subscripts

3. check the solubilities. If one is insoluble it is a precipitation reaction

4. Balance the Equation

molecular equation

Does not show ionic character

complete ionic equation

for double displacement reaction

shows ionic character

all soluble strong ions have their charges shown

spectator ions

An ion that exists in the same form on both the reactant and product sides of a chemical reaction. Thus it has no direct role in the reaction

define net ionic equation

the equation consisting only of elements directly involved in the reaction

to form:
cross out anythin that doesn't change from left to right side

What remains is your equation

If every ion in an ionic equation is a spectator...

No reaction happens

What compounds are strong electrolyts

all ionic compounds, strong acids

What compounds are weak electrolytes

weak acids, weak bases

What compounds are nonelectrolytes

anything that is not an ionic compound, weak acids, or weak bases

Strong acids

HClO₄
HClO₃
H2SO₄
HNO₃
HCl
HBr
HI

-ic acids are strong
-ous acids are weak

Strong bases

LiOH
NaOH
KOH
RbOH
CsOH
Ca(OH)2
Sr(OH)2
Ba(OH)2

Group A1
Group 2A

acids

Ionize in aqueous solutions to form H+(aq), hydrogen ions

Hydrogen ions are essentially protons

hydrogen ions

just a proton (Hydrogen is just 1 proton and 1 electron)

Monoprotic vs diprotic

monoprotic - acid that yields 1 H+ ion

diprotic - acid that yields 2 H+ ions

base

substances that accept and react with H+ and produce OH- hydroxide ions when they dissolve

A base does not have to have OH in it because it can often accept the O from the soultion

Substance that consumes H+

How to find out if a substance is a strong electrolyte, weak electrolyte, or a nonelectrolyte

neutralization action

when an acid and a base is mixed.

The products do not have any of the characteristics of the reactants

What do neutralization reactions between metal hydroxides and acids produce?

salts and water

salt

any ionic compound whose cation comes from a base and it's anion comes from an acid

Oxidation reduction reactions

electrons are transferred from one reactant to another

corrosion (redox reaction)

The conversion of a metal to a metal compound by a reaction betweeen the metal and some substance in it's enviornment

i.e. the metals ions loose an election, becoming cat ions, and combines with anions in the envirnment to form an ionic compound

oxidized

when an atom, ion, or molecule has become more positive (looses electrons)

oxidation

the losing of electrons

reduced

when an atom,ion, or molecule has gained electrons

reduction

the gaining of electrons (becoming more negative`)

Oxidation is always followed by

reduction

oxidation number

a number assigned to an element in chemical combination that represents the number of electrons lost (or gained, if the number is negative) by an atom of that element in the compound.

Oxidation reduction reactions

what is the oxidation number for monatomic ions

its the same as their charge

what is the oxidation number for neutral molecules and polyatomic ions

a hypothetical charge determined by artificially dividing up the elections in the molecule/ion.

What are the rules for determining oxidation numer

1. In elemental for the oxidation number is 0 (one element in the formula, no over all charge)

2. for a monatomic ion the oxidation number is equal to the charge of the ion (Al3+ redox number is +3)

3. nonmetals usually have negative oxidation numbers but not always
a. Oxygen is -2 except in peroxides
b. Hydrogen is usually +1 when bonded to nonmetals and
-1 when bonded to metals
c. fluorine is always -1 . The other halogens are usually -1 in
most binary compounds But when bonded with oxygen
(oxyanions) they are positive.

Certain elements have same oxidation number in all/most of their compounds
a. 1A metals are always +1 in compound
b. 2A metals are always +2 in compound
cl Fluorine is always -1 in compound

4. The sum of oxidation numbers in a neutral compound is zero. The sum of the oxidation numbers in a polyatomic ion equals said ion's charge.

5. Max oxidation number of group A is its group number (roman numeral)

6. For nonmetals the minimum oxidation number is group number minus 8.

elemental form

A substance that cannot be broken down into simpler substances by chemical means. An element is composed of atoms that have the same atomic number, that is, each atom has the same number of protons in its nucleus as all other atoms of that element.

how to distinguish between charge and oxidation number

charge = 2+

oxidation number = +2

the pattern of a reaction between a metal and an acid or metal salt

A + BX ---> AX + B

displacement reaction

a chemical reaction in which a more reactive element displaces a less reactive element from its compound. Both metals and non-metals take part in displacement reactions.

activity series

a list of metals arranged by ease of oxidation

active metals

metals that are most easily oxidized

the alkali metals and alkaline earth metals (maybe more)

noble metals

transition elements from groups 8B to 1B (maybe more)

they have low reactivity

activity series

predict the outcome single displacement reactions

Which metals can be oxidized by which metals

Each metal on the activity series can be oxidized by metals lower than it on the table

Anything under hydrogen on the activity series cannot...

react with acids to form H2

molarity equation

The concentration of a solution by how many moles of a solute is in it. (M)

MOLES OVER L

dilution

process of adding a concentrated version of a solution to another solution (usually water) gain a lower concentration of the concentrated solution.

This is common for commonly used chemicals.

Moles of solute before dilution =

moles of solute after diultion

Equation for dilution (can only be used for a pure solvent)

M x V (of concentration) = M

What is special about the ferric ion in regards to Exchange (Metaphesis) reactions

Fe3 stays Fe3 when moving from products to reactants

Gas-forming reactions

some double displacement reactions don't give expected products

When carbonate/bicarbonate....

Oxidizing agent vs reducing agent

oxidizing agent - substance that is reduced

reducing agent- substance that is oxidized

single replacement (single displacement) reaction

A + BC ---> AB + C

are redox reactions

Using molarity in stoichiometry flow chart

Titration flow chart

Single displacement reaction of halogens

Reactants and products of combustion reactions

what is H(OH)

H2O

Mass percent of solute (way of determining concentration other than molarity)

mass of solute/mass of solution x 100

Exceptions

Oxidation number rules

Solubility Rule 1

all nitrates are NO are soluble

Solubility Rule 2

All acetates are soluble

Solubility Rule 3

All compounds of group 1A cations (alkali metals) are soluble

Solubility Rule 4

Halides are soluble except for Ag, Hg, PB

Hydrochloric Acid

HCl Strong acid

Hydrobromic Acid

HBr strong acid

Hydroiodic Acid

HI strong acid

Chloric acid

HClO₃ strong acid

Perchloric acid

HClO₄ strong acid

Nitric Acid

HNO₃ strong acid

Sulfuric acid

H₂SO₄ (first proton) strong acid

Group 1A metal hydroxides

LiOH, NaOH, KOH, RbOH, CsOH Stong base

Heavy Group 2A metal hydroxides

Ca(OH)₂ Sr(OH)₂ Ba(OH)₂Strong base

Weak acid

HF

Acetic Acid

weak acid

Formic acid

weak acid

Weak base

NH₃

LEO the lion says GER

Lose electrons oxidation; Gain Electrons Reduction

Acid to base containing CO₃⁻ + HCO₃⁻

need H₂O (l) + CO₂ (g)