Gen Chem

Elements

Physical matter is made up of…

Atom

The smallest particle (unit) of an element

Molecule

Two or more atoms bonded together (same or different atoms)

Compound

Two or more DIFFERENT atoms bonded together

Pure substance

When two or more elements chemically bond in a fixed ratio

Monoatomic

Single-atom formula (Na, Cs, Mg, C)

Diatomic elements

DO NOT exist stably as an uncharged single atom

• Have No Fear of Ice Cold Beer

• Hydrogen (H2)

• Nitrogen (N2)

• Fluoride (F2)

• Oxygen (O2)

• Iodine (I2)

• Chlorine (Cl2)

• Bromine (Br2)

Allotropes

Some elements that CAN but don’t have to exist in nature with various elemental formulas

• O2 = oxygen, O3= ozone

Ionic compounds

Metal + nonmetal

Molecular compound

Two or more non-metals (covalent bonds)

Always have a -1 charge, LOVE to take electrons

F, Cl, Br, I

Always has -2 charge, will take electrons

O, S, Se

Has -3 charge, will take electrons

N, P

• How to name ionic compounds

• Name the metal

• Write the metals oxidation state as a Roman numeral in parenthesis

  • Skip this step for columns 1 (always +1) and 2 (always +2) as well as Al (+3), Zn(+2), Cd(+2), Ag(+1)

• Name the nonmetal use an -ide ending except for polyatomic ions

  • Ex: MgF2: magnesium fluoride

  • Ex: Al2O3: Aluminium Oxide

  • Ex: FeCl2: Iron (II) Chloride

Polyatomic ions

Ions that are made up of 2 or more atoms

Ammonium

NH4+

Hydronium

H3O+

Mercury (I)

Hg2 2+

Dihydrogen phosphite

H2PO3-

Dihydrogen phosphate

H2PO4-

Hydrogen carbonate

HCO3-

Hydrogen sulfite

HSO3-

hydrogen sulfate

HSO4-

Nitrite

NO2-

Nitrate

NO3-

Hydroxide

OH-

Acetate

CH3COO-

Chromite

CrO2-

Cyanide

CN-

cyanate

CNO-

Thiocyanate

CNS-

Permanganate

MnO4-

Hypochlorite

ClO-

Chlorite

ClO2-

Chlorate

ClO3-

Perchlorate

ClO4-

Hypobromite

BrO-

Bromite

BrO2-

Bromate

BrO3-

Perbromate

BrO4-

Hypoiodite

IO-

Iodite

IO2-

Iodate

IO3-

Periodate

IO4-

Azide

N3-

Hydrogen phosphite

HPO3 2-

Hydrogen phosphate

HPO4 2-

Carbonate

CO3 2-

Sulfite

SO3 2-

Sulfate

SO4 2-

Thiosulfate

S2O3 2-

Oxalate

C2O4 2-

Chromate

CrO4 2-

Dichromate

Cr2O7 2-

Peroxide

O2 2-

Disulfide

S2 2-

Oxide

O2-

Sulfide

S2-

Phosphate

PO4 3-

Arsenite

AsO3 3-

Arsenate

AsO4 3-

Nitride

N3-

Naming molecular compounds

• Give appropriate numerical prefix to the first element, unless it is only one atom

• Name the first element using its regular name on the table

• Give the appropriate numerical prefix to the second element

• Name the non metal using and -ide ending

• Ex: N2O: dinitrogen monoxide

naming binary atoms

• binary atoms: H bonded to one other element

• Hydro + insert the name of element 2, replacing “-ine” with “-ic acid”

• Ex: HF: hydrofluoric acid

Naming oxyacids

• Oxyacid: H bonded to middle atom bonded to O: H-middle y-O

• Identify the polyatomic anion

• Lowest # of O: hypo + insert the name of element 2, replacing “ine” with “ous acid”

• 3rd highest # of O: insert the name of element 2, replacing “ine” with “ous acid”

• 2nd highest # of O: insert name of element 2, replacing “ine” with “ic acid”

• Highest # of O: “per” + insert the name of element 2, replacing “ine” with “ic acid”

• In other words: use hypo for the formula with fewest oxygen atoms, and per for the formula with most oxygen atoms

Polyatomic anions and oxyacids

• Polyatomic anions end in -ate typically have acids ending in -ic acid

• Polyatomic anions ending in -ite typically have acids ending in -ous acid

Strong acids

• HCl

• HBr

• HI

• HClO3

• HClO4

• H2SO4

Terra

10^12

Giga

10^9

Mega

10^6

Kilo

10³

Centi

10^-2

Milli

10^-3

Micro

10^-6

Nano

10^-9

Cubic to mL

1 cm³ = 1 mL

Density

Density = mass / volume

Meter to feet

1m = 3.28 ft

Mile to kilometer

1 mile = 1.609 kilometers

Precision

How close a series of measurements are to each other

Accuracy

How close the measurement is to reality

% error

% error = ((actual - theoretical) / theoretical) * 100

Measuring accuracy

Beaker, Erlenmeyer flask < graduated cylinder < buret < volumetric flask < volumetric pipette

A mole

• 6.022 × 10^23

• The # of atoms in a sample that weigh that elements atomic weight

Combustion rxn

• rapid reaction in which a hydrocarbon (CxHy) or an alcohol (CxHyOH) reacts with oxygen (O2)

• (CxHy) or (CxHyOH) + O2 —> CO2 + H2O

  • products are ALWAYS CO2 + H2O

• In order to get complete combustion, you always have excess O2 in the reactants

Decomposition

One substance in the reactants —> two or more products

Empirical formulas

Formulas that give only the most reduced whole number ratio of each atom

Percent composition

If given the MOLECULAR formula, you can calculate what percent of each element make up the molecular weight

2 ways to solve percent composition

1. Given formula and asked for specific element’s percent

2. Given the mass percent of each element and asked to determine the compounds formula

• Assume 100g of the sample

• Divide by each elements respective weight

• Divide by the smaller number from the previous step

• If the answer is close to a whole number, go to next step. If not, multiply by 2 or 3 to get them to whole numbers

• These numbers are the subscript of the empirical formula

Empirical formula —> molecular formula

1. Divide molecular weight by the weight of empirical formula

2. Multiply each subscript by that answer

Limiting reactant if the problem say excess

BCC:

1. Balance the equation

2. Convert to moles

3. Use the coefficients in the equation to transform the moles of things you know into moles of what you don’t know

Limiting reactants that don’t say excess

BCDS:

1. Balance the reaction

2. Convert to moles

3. Divide moles/coefficients

4. Smallest one = limiting reactant

% yield

% yield = actual yield / theoretical yield * 100

• actual: given in the problem

• Theoretical: what you calculate from limiting reactants

Theoretical yield

Amount of product you should get when running an experiment if everything goes perfectly

Mass %

Mass of solute x 100 / mass of solution

Single replacement

One element replaces another in a compound

• A + BC —> B + AC

Double replacement

2 compounds exchange components to form 2 new compounds

• AB + CD —> AD + BC

Molarity

Moles / liters

Molar Mass

Compound mass / moles of compound

1 mol of an ideal gas

Occupies 22.4 L