CHEM CHECKLISTS

ATOMS IONS AND COMPOUNDS

Isotopes

atoms of the same element with the same number of protons but different numbers of neutrons, different masses

work out

number of protons, neutrons, electrons for atoms and ions

relative isotopic mass

relative atomic mass

the weighted mean mass of an atom

compared to 1/12th the mass of an atom of carbon-12

using mass spectrometry

y- axis is intensity: relative amount of each type of ion detected used as rel abundance

x axis is mass/charge ratio of detected ion used as RAM

most abundant ion peak with the greatest intensity is base peak usually assigned rel intensity of 100

calculating RAM using MS- from relative abundances of isotopes

the sum of (RAM of isotope x % abundance of isotope) divided by 100

formulae of ionic compounds from ionic charges

balance charges of two elements, use periodic table, knowledge of memorised charges

predict ionic charge from position of an element in the PT

G1 : charge of 1+

G2: charge of 2+

G5: charge of 3-

G6: charge of 2-

G7 charge of 1-

G8 no charge, full outershell

recall the names of 6 polyatomic ions

hydroxide OH-

nitrate NO3 -

sulfate SO4 2-

carbonate CO3 2-

phosphate PO4 3-

ammonium NH4 +

recall transition elements ions

silver Ag+

zinc Zn 2+

Aluminum Al 3+

iron 2 or 3

copper 2 or 3

balanced normal chemical equations

use ions to know the formulae for ionic compounds

add numbers to balance

all acids are aq, all metals are solids

for now metal + acid → salt + hydrogen

metal hydroxide/ oxide/ base + acid → salt + water

metal carbonate + acid → salt + water + CO2

reactions involving ammonium ions will produce ammonia gas NH3

list of acids

ntiric HNO3

sulfuric H2 SO4

add more once u know them

construct balanced ionic Es

state symbols should be given in question,

first thing ever is to balance

use ions to know the formulae for ionic compounds anything that is aq on both sides spectator ion so not included

write out all ions involved

other than that solids liquids and gases remain check the charges are the same on both sides, may need to balance for example 2H+ so check charges

dont forget to mention charges in your answer for aq only not for s, l or g

for hydrogen gas it is H2 not 2H

blocks of periodic table

SDPF

s for first two groups

D for transition metals

P for group 5-8

f for the bottom two rows

AMOUNT OF SUBSTANCE

relative molecular mass

The weighted mean mass of a molecule of a compound compared with 1/12 of the mass of an atom of carbon-12 (simply RAM)

relative formula mass

the weighted mean mass of the formula unit of a compound compared with 1/12th of the mass of an atom of carbon-12 (RAM simply)

amount of substance

the quantity whose unit of the mole used as a means of counting any species such as atoms ions and molecules

mole

unit for amount of substance, amount of any substance containing as many elementary particles as there are carbon atom in exactly 12g of carbon-12 isotope that is 6.02 × 10^ 23

amount of substance containing AV’SC number of atoms

avogadro constant

The number of atoms in one mole of the carbon-12 isotope (6.02 × 10²3)

molar mass

The mass per mole of a substance in units g/mol

molar gas volume

volume per mole of gas molecules at a stated T and P—> 24 dm³ mol -1

empirical formula

simplest whole number ratio of atoms of each element present in a compound

molecular formula

The number and type of atoms of each element in a molecule

calculating both EF and MF composition of mass

for EF: mass or % composition DIVIDED BY RAM (molar mass)

divide by the smallest number for the EF

when given molar mass/ RAM of MF divide that by the RAM of EF to get a factor, multiply the EF by this factor to get MF

anhyrdous

Containing no water molecules

hydrated

Crystalline compound containing water molecules

water of crystallisation

Water molecules within the structure of the crystal

formula of a hydrated salt from %composition or experiment results

Salt compound • x H2O need to find EF of compound and water

calculations mass= mr x mol

mass (g)= molar mass (g mol-1) x moles (mol)

Molar mass is just Ar

calculations involving molar gas volume

moles = volume // molar gas volume

Volume = moles x 24 dm³ mol -1

calculations involving concentration, volume, moles

moles (mol) volume (dm³) X concentration (mol dm³)

1dm³= 1000 cm³

To go from mol dm³ to g dm³ MMMultiply by RAM , g dm³ used for mass/ volume = concentration

ideal gas equation pV= nRT

stoichmetric relationships

calculating percentage yield of reaction

Actual yield // theoretical yield x 100

calculating atom economy

(Mr of desired products // Mr of all products) x 100

desacribe techniques and procedures required during experiments requiring measurement of mass, volume of solutions and gas volumes

benefits for sustainibillity of developing chemical processes with a high atom economy

BONDING

Describe ionic bonding

strong electrostatic attraction between positive and negative ions

Construct dot and cross diagrams for ionic compounds

Explain the solid structures of giant ionic lattices

Results from oppositely charged ions strongly attracted in all directions, each Na+ ion is surrounded by 6 Cl- ions and vice versa , each ion is surrounded by OCI forming giant ionic laatice

Properties of ionic compounds

Can be explained in terms of giant ionic lattice structure and ionic bonding

High MP and BP

Dissolve in polar solvents such as water

Conduct electricity when in molten state or dissolved in water doesn’t conduct when in solid state

MP and BP

All solids at room temp, large amounts of energy, high temps needed to overcome strong electrostatic forces of attraction between oppositely charged ions in the giant ionic lattice , higher for ions with greater ionic charges as there is stronger attraction between ions, higher for larger sized ions as the ionic attraction is stronger

Solubility

Solubility requires ionic lattice to be broken down, water molecules must attract and surround the ions

polar water molecules break down the lattice and surround each ion in solution, in a compound made of ions with large charges the ionic attraction may be too strong for water to be able to break down the lattice structure, solubility of an IC depends on relative strength of the attraction within the giant ionic lattice and the attractions between ions and water molecules, solubility decreases as ionic charges increase

Conductivity

In a solid state IC doesn’t conduct electricity as the ion safe in a fixed position in the GIL , not free to move so no mobile charge carriers

When liquid or dissolved in water (aq state) solid ionic lattice breaks down and ions are free to move as mobile charge carriers

Describe covalent bonds

Strong electrostatic attraction between a shared pair of electrons and the nuclei of bonded atoms occurring between atoms in non metalling elements, compounds of non metallic elements and polyatomic ions

Construct dot and cross diagrams of molecules and ions

Construct doy and cross diagrams of M and I to describe single covalent bonding

Single C-C bonds for example, the one you are used to