Studied by 18 people
What is the structural formula?
tells you the way in which the atoms in a particular molecule are bonded, done by a diagram (displayed formula) or written (simplified structural formula)
What type of structural formula is this?
displayed/diagram
What type of structural formula is this?
simplified/written
What is the molecular formula?
tells you the actual number of atoms of each element in one molecule of the compound or element
E.g. H2 has 2 hydrogen atoms, HCl has 1 hydrogen atom and 1 chlorine atom
Whats an empirical formula?
simplest whole number ratio of the atoms of each element present in one molecule or formula unit of the compound (js simplest form)
eg in image
The formula of an ionic compound is always…
empirical
The formula of an organic compound..
often has diff empirical and molecular formula
Show the charges of the common ions
KEEP IN MIND you find the charge of elements from its grp
Grp 1-3 = 1+,2+,3+
Grp 4= transition
Grp 5-8= 3-,2-,1-
KEEP IN MIND Roman numeral next to the element tells you the charge on the ion, e.g. copper(II) ions have a charge 2+
How do we deduce/write formulas for ionic compounds?
Swap and Drop method (drop and switch)
Only add the brackets if needed
What are some keywords to turn word problems to equations?
When naming a compound what element goes first?
Metal
What are the naming rules when there is 2 elements in a compound?
NM as 2nd name
ending changes to -ide
What are the naming rules when there are 3 elements in a compound?
NM 2nd name
ending changes at -ate if the 2nd last element is bonded to a oxygen element
What is relative molecular mass?
Mr, the total mass of a molecule
What is relative formula mass?
total mass of an ionic compound
How do we calc Mr?
Sum of all Ar values
dont forget the subscipts and brackets
What is the mole?
measure of amount of a sub
How many particles in 1 mol of a sub?
6.02×10²³, Avogadro’s constant
What is molar mass?
mass of 1 mole of a sub
What is the unit of molar mass?
g/mol
Relation between Ar and MM?
for an element, MM=Ar
Relation between Mr and MM?
for a compound, MM=relative FM/Mr
What is Avogadro’s law?
At the same conditions of T and P, equal amounts of G occupy the same V
What is the molar gas volume (RTP)
1 mol of a gas occupies 24 dm³ at rtp
How can you calc RTP in dm³?
How can you calc RTP in cm³?
How to calc moles in a solid?
moles=mol mass=g MM/Mr=g/mol
How can we calc the moles or masses in a chemical eq?
remeber to balance
What is the limiting reactinant?
The LR is the reactant that is used up first
How to find LR?
when performing reacting mass calculations, the limiting reactant is always the number that should be used as it indicates the maximum possible amount of product
What is concentration?
Amount of solute in a specific volume of solvent
What is solute?
a S sub dissolved in L
Whats solvent?
the L the solute is dissolved in
Concentration unit?
g/dm³ or mol/dm³
How to calc concentration?
How to calc volume or conc in a chemical eq?
How to calc empirical formula?
steps 1 and 4 depend on the qs
How to calc molecular formula?
Step 1: Find the relative formula mass of the empirical formula
Step 2: Use the following equation:
Step 3: Multiply the number of each element present in the empirical formula by the number from step 2 to find the molecular formula
eg of molecular formula
How to deduce formulae of hydrated salts?
What is yield?
The term used to describe the amount of product you get from a reaction
Why do we never get 100% yield?
Some reactants may be left behind in the equipment
The reaction may be reversible and in these reactions a high yield is never possible as the products are continually turning back into the reactants
Some products may also be lost during separation and purification stages such as filtration or distillation
There may be side reactions occurring where a substance reacts with a gas in the air or an impurity in one of the reactants
Products can also be lost during transfer from one container to another
What is actual yeild?
the recorded amount of product obtained
What is theoritical yield?
theoretical yield is the amount of product that would be obtained under perfect practical and chemical conditions
What is the precentage yield?
compares the actual yield to the theoretical yield
give a %yield eg
How do you calc % mass?
eg of %mass?
How to calc %purity?
eg of % purity?
Note 
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