Chemistry - SL Stoich Formulas & Equations

definitons + formulas and some bonding stuff

covalent molecular

• doesn’t conduct electricity

• soft

• low melting/boiling points

covalent network

• doesn’t conduct electricity

• hard substance

• no free moving charged particles

• high melting point/boiling point (many covalent bonds need to bebroken)

metallic bonding

• conducts electricity well

• malleable

• usually high melting/boiling points

• conducts heat well

ionic bonding

• metal and non-metal bonding

• transfer of electrons

• high melting/boiling point

• can conduct electricity only in molten state

covalent bonding

• non-Metals ONLY

• SHARING of electrons

Reactions in which elements burn in air or oxygen

• element + oxide (g) → elemental oxide (s)

• eg. Lithium (s) + Oxide (s) → Lithium Oxid (s)

Combustion

1. Hydrocarbon + Oxygen -→ Carbon Dioxide + Water

2. eg. ethene + oxygen → carbon dioxide (g) + water (l/g

Reactive Metal + Water

• Metal + Water → Metal Hydroxide (aq)+ Hydrogen

• Potassium + Water → Potassium Hydroxide (aq) + Hydrogen (g)

• 2K (g)+ 2H2O (l) → 2KOH(aq) + H2 (g)

Metal + Acid (metal hydroxide or oxide)

• metal + acid → Salt + Water

• zinc + hydrochloric acid → Zinc chloride (aq) + Water (l)

• Zn + 2HCI → ZnCl2 (aq) + H2O (l)

Acid + Base (carbonate/hydrocarbonate)

• Carbonate + Acid → salt + carbon dioxide + water

• calcium carbonate (s) + nitric acid (aq) → calcium chloride (aq) + Carbon dioxide (g) + water (l)

• CaCO3 (s) + HNO3 (aq) → CaCl2 (aq) + CO2 (g) + H2O (l)

Generally Soluble IONS (no exceptions)

• Na (+)

• NO3 (-)

• NH4 (+)

• K (+)

• CH3COO (-)

Generally Soluble - Cl (-), Br (-), I (-)

Exceptions: Ag (+) , Pb (+)

General soluble SO4 (2-), Cr2O7 (2-)

Exceptions:

• Pb (2+)

• Ba (2+)

• Ag (+)

• Ca (2+)

Generally insoluble - CO3 (2-), PO4 (3-), S (2-)

Exceptions:

• NA (+)

• K (+)

• NH4 (+)

Generally Insoluble - OH (-)

Exceptions:

• Na (+)

• K (+)

• NH4 (+)

• Ba (2+)

• Ca (2+)

• Barium & Calcium are soluble with hydroxide ONLY

NA

• Avagadros Constant

• 6.02 x 10^23

Significant figures:

How many dp’s are used in the final anser of addition & subtraction

no more dp’s than the term with the least number of dp’s

Rounding should always be…

last step

Significant Figures:

How many dp’s does multiplication/division - final answer

same as the factor with the least number of figures

Definition of a mole

A mole of substance is the amount of substance that contains as many specified particles (ie. atoms, ions, molecules, electrons and so on) as there are atoms of carbon-12 in exactly 12g carnon-12

1 mole =

• 6.02 x 10^23

• Avagadros Constant

number of moles

• number of particles/avagadro’s number

• n for moles is lowercase bc divided

number of particles

number of moles x avagadro’s number

n

no. of moles

N

no. of particles

m(g)

mass

M

Molar mass

Mass =

• number of moles x molar mass

• m(g) = n(mol) x M (gmol^-1)

Combined equation

• can find number of particles if given only. mass & vice versa