Unit 4 Thou Shalt Not Forget, AP Chemistry

Percent Yield

(Actual Yield/Theoretical Yield) x 100%

compounds that contain carbon and hydrogen yield

CO2 and H2O when burned

An acid

donates H+ in aqueous solutions

A Base

accepts H+ in aqueous solutions

Acid + Base

salt + water

Oxidation

loss of electrons

Reduction

gain of electrons

oxidizing agent

Accepts electrons and becomes reduced.

reducing agent

Donates electrons and becomes oxidized.

Group 1 compounds, ammonium, and nitrates

are soluble

evidence of chemical change..

precipitate forms, experience a change of energy in the form of heat or light, observe a color change, see formation of gas, or observe an electrical current

all soluble ionic compounds are

strong electrolytes

number of moles =

mass of sample divided by molar mass

moles =

M (concentration) divided by volume (L)

I mol off any ideal gas at STP occupies

a volume of 22.4L

% yield =

(actual yield of product/ theoretical yield of product) x100

titrant

substance with a known concentration

equivalence point

point at which the stoichiometric molar ratio has been achieved

end point

the observable event that occurs at the equivalence point

oxidation is the .... reduction is ... of electrons

loss, gain

Brønsted - Lowry definition of acids and bases

deal with whether they accept or donate electrons

Driving forces

changes that indicate a chemical reaction

%Yield =

(actual yield / theoretical yield) x 100

Physical Change

Chemical Change

Intermolecular Forces

Intramolecular Bonds

If it is reduced

it gains electrons

If it is oxidized

it loses electrons

Spectator ions

ions that aren't involved in the ionic equation

Particles in solids

have little energy and vibrate

Particles in liquids

have a medium amount of energy and move around

Particles in gases

have a large amount of energy and move around freely

state changes

Solid - liquid = melting

Liquid - solid = freezing

Liquid - gas = evaporation

Gas - liquid = condensation

Gas - solid = sublimation

Solid - gas = deposition

insoluble compounds

Hydroxides (except Group 1 and Ammonium), Carbonates, Phosphates, Chromates, and Sulfides (except Group 1 and Ammonium and the Sulfides of Group 2)

net ionic equation

an equation for a reaction in solution showing only those particles that are directly involved in the chemical change

soluble compounds

Group 1, ammonium, nitrates

Standard Temperature and Pressure (STP)

A temperature of 273 K and a pressure of 1.00 atm

1 mole of ideal gas at STP

22.4 L

Neutralization

A reaction of an acid with a base, yielding a solution that is not as acidic or basic as the starting solutions were.

titrant

a solution of known concentration

_________ determines the number of products formed

limiting reactant

percent yield formula

actual yield/theoretical yield x 100

Unit 4 1

Strong electrolytes have a large number of ions and is completely ionized. It also conducts electricity well. Weak electrolytes have very few ions present and is partially ionized. It also conducts electricity weakly. Non electrolytes have no ions and can not conduct electricity. It is not ionized. Most molecular compounds are weak or non electrolytes.

Unit 4 2

Ionic equations show the degree of ionization taking place like NaCl(s) --> Na+(aq) + Cl-(aq). Net ionic equations or ionic equations that are re-written to only show the ions that take part in the reaction. To do this, you would cancel out ions on both sides, which would leave you with the ions that take part in the reaction. Ex. Ag+(ag) + NO3-(aq) + K+(aq) + Br-(aq) --> AgBr(s) + K+(aq) + NO3-(aq). Since NO3-(aq) and K+(aq) are on both sides, you would cancel them, leaving you with Ag+(aq) + Br-(aq) --> AgBr(s)

unit 4 3

If you have a picture of 2 H2 gas molecules and one O2 molecule and another picture of 2 H2O molecules, it represents the balanced equation of 2H2 + O2 --> 2H2O

Unit 4 4

If there are changes in intermolecular bonds(Hydrogen, dipole-dipole, LDF) then there is a physical change but a change in intramolecular bonds(ionic and covalent) is a chemical change.

Unit 4 5

The limiting reactant is the reactant that is completely consumed and it determines how much product is formed.

Unit 4 6

Synthesis(combination) is a REDOX reaction that makes 2 or more elements into a single compound.

Decomposition is a REDOX reaction that has a compound split into its original elements.

Single displacement is a reaction where an atom or ion in a compound is displaced by another atom or ion of another element. This is usually sen between metals.

Double displacement is when two elements in a reaction switch or join a different element. Combustion is a reaction where a compound or element "burns" oxygen. Usually has CO2 and H2O on the product side.

Unit 4 7

Remember that hydroxides are insoluble except for group 1 and ammonium.

Carbonates, phosphates, chromates, and sulfides are insoluble except when paired with Group 1, ammonium, and the sulfides of group 2.

Unit 4 8

Knowing the result of the formation of colored precipitates, like how SO4 2- paired with Ba 2+ will form a white precipitate of BASO4(s), might help you answer a question in the future.

Unit 4 9

All metals above hydrogen in a series will displace it in an acid.

All metals below hydrogen will not displace it from an acid or water

Unit 4 10

The oxidation number of an element when uncombined is always zero.

The sum of the oxidation number in a neutral substance is always zero.

ionic solution

An ionic compound dissolved in a liquid to form an electrolyte. Can be identified by the ability to conduct electricity

strong electrolyte

any compound whose dilute aqueous solutions conduct electricity well; this is due to the presence of all or almost all of the dissolved compound in the form of ions

weak electrolyte

any compound whose dilute aqueous solutions conduct electricity poorly; this is due to the presence of a small amount of the dissolved compound in the form of ions

STP (standard temperature and pressure)

273 K and 1 atm and volume of 22.4 L

water

can be an acid and a base

acid

any compound that forms H+ ions in solution (donates H+ ion)

base

a compound that produces hydroxide ions in solution (accepts/ receives H+ ion)

oxidation

loss of electrons

reduction

gain of electrons

soluble

group 1, ammonium, nitrates, chlorates, hydrogen carbonates, chlorides, bromides, iodides, and sulfates

nonsoluble

hydroxides, carbonates, phosphates, chromates, and sulfides

oxidation number

Positive or negative number that indicates how many electrons an atom has gained, lost, or shared to become stable (in front of the element)

charge number

number of protons and number of electrons (behind element)

oxidation number concept

binary compounds with metals, group 17 are -1, group 16 are -2, group, and group 12 are -3

solid to liquid

melting

liquid to gas

boiling

gas to liquid

condensing

solid to gas

sublimation

gas to solid

deposition

liquid to solid

freezing

standard conditions

1M & 1 mol & 273 K & 1.0 atm

What changes in PHYSICAL changes?

INTERMOLECULAR forces are broken

What changes in a CHEMICAL change?

INTRABONDING forces are broken

OXIDATION

LOSS of e-

REDUCTION

GAIN of e-

titrant

added to the analyze

oxidized

loses electrons

reduced

gains electrons

spectator ions

Ions that do not take part in a chemical reaction and are found in solution both before and after the reaction

reducing agent

Donates electrons and becomes oxidized.

oxidizing agent

Accepts electrons and becomes reduced.

1 mole ideal gas

22.4 L

strong electrolyte

completely dissociates into ions

weak bases

weak acids

ammonia and organic

organic, butanoic, propanoic, HF

strong bases

strong acids

1 and 2 hydroxides

HCL, HBr, HI, HNO3, H2SO4, HClO4

Physical Change Examples

melting, boiling, condensing, sublimation, freezing, reverse sublimation or deposition

Driving Forces

color changes, heat changes, light forms, precipitate forms, formation of a gas, electrical current

Strong Electrolyte

a solution in which a large portion of the solute exists as ions; excellent conductor of electricity; completely ionized; all soluble ionic compounds and a few molecular compounds

Weak Electrolyte

conducts electricity poorly; only few ions present; partially ionized; most molecular compounds

Non-Electrolyte

no ions present in solution; cannot conduct electricity; not ionized; most molecular compounds

Molarity

moles of solute/liters of solution

Molar Mass

gRT/PV

Percent Yield

actual yield/theoretical yield x 100

Combustion Analysis

1. Calculate the moles of CO2 produced which is also mol of C

2. Calculate the moles of H2O produced, then multiply by 2 for mol of H

3. Calculate the mass of C and H presented in the combusted sample

4. If there is another element present in the combusted substance then calculate its mass then turn to moles

5. The results from #4 should be convenient ratio and give the empirical formula

Titration

experimental method of analysis that utilizes concentrations of solutions

Titrant

known concentration

Analyte

unknown concentration

Equivalence Point

point at which stoichiometric molar ratio has been reached

End Point

observable event that occurs at the equivalence point; color change

Acid

a substance that donates hydrogen ions in solutions