auer mod 2.1 mols Flashcards
what is Avogadro’s number (definition)
the number of particles/ atoms/ molecules in one mole of any substance
what is Avogadro’s number (number)
6.02x10^23
what’s Ar
the relative atomic mass of an element “neutron + proton”
what’s Mr
the sum of all the Ar’s of all the atoms present in the substance. Its the relative molecular mass
what’s percentage yield
the mass or moles of product obtained expressed as a percentage of what should be produced.
what’s atom economy
a measure of the proportion of reactants that become useful
what’s percentage yield equation
actual yield
_____________ x 100
theoretical yield
what’s atom economy equation
mass of desired products
____________________ x 100
total mass of reactants
what are 5 reasons why percentage yield is not normally 100%
- reactants or products may be left behind in apparatus.
- separation and purification may result in loss of some of the product
- the reaction may be at equilibrium and not go to completion
- The reactions may not be pure
- side reactions may occur leading to side products
what numbers from equations are used in atom economy
large numbers as well as the small numbers
what is a standard solution
a solution of known concentration. It can be prepared by dissolving a known mass of a solid in solvent and making it up to an exact volume.
what is the limiting reactant
the reactant that is not in excess
what is pressure proportional to
temperature
what is volume proportional to
temperature
what is pressure inversely proportional to
volume
what is the ideal gas equation…
pV=nRT
ideal gas equation: p and what its measured it
p=Pressure (Pa)
ideal gas equation: V and measurement
V= Volume (m^3)
ideal gas equation: n and measurement
n= amount of substance (mol)
ideal gas equation: R and measurement
R= ideal gas constant (8.314Jk^-1mol^-1
ideal gas equation: T and measurement
T=temperature (K=kelvin)
how do you get from dm^3 to m^3
divide by 1000
how do you get from cm^3 to m^3
divide by 1000000
how do you get from dm^3 to cm^3
multiply by 1000
how do you get from K to C
subtract 273
what does the molecular formula tell us
the molecular formula tells us the number and type of atoms of each element in a molecule
what does the empirical formula tell us
the simplest whole number ratio of atoms in a molecule
the molecular formula for butene is C4H8, what’s the empirical formula
CH2
How do you find concentration from mass and volume
conc= mass/vol
what does an oxidation reaction involve
the loss of electrons
what does a redox reaction involve
oxidation and reduction occurring at the same time
what’s a redox reaction
where oxidation and reduction occur simultaneously in a reaction because one species lose electrons which are the donated and gained by another species.
if the oxidation number increases, is it reduced or oxidised?
oxidised (loss of electrons)
formula for hydrochloric acid
HCL
formula for nitric acid
HNO3
formula for sulfuric acid
H2SO4
3 strong bases?
lithium hydroxide
sodium hydroxide
potassium hydroxide
what does water of crystallisation mean
when ionic compounds form, they often have molecules of water stuck in them.
formula for ethanoic acid
CH3COOH
what is an acid
a species able to donate protons ( H+ (hydrogen) ions)
what is a base
a species able to accept protons ( via a lone pair)
what are all alkalis
bases
what are alkalis in terms of bases
water soluble bases ( metal hydroxides and NH3)
what is a standard solution and what is it used to do
a standard solution has a known concentration, its used in a titration to find the concentration of another substance
what happens when an acid is added to water ( what does the acid release)
the acid releases H+ ions into solution
what are the two common bases and what’s another base
- metal oxides
- metal hydroxides
- ammonia
what happens to alkalis when dissolved in water
they release OH- (aq) ions when dissolved in water
what are the 3 common alkalis
NaOH
KOH
NH3
acid+ carbonate??
=salt + carbon dioxide +water
acid+ metal oxide??
=salt+ water
acid + alkali??
= salt+ water
acid + metal??
= salt + hydrogen
what does hydrated mean
the crystalline form containing water
what does anhydrous mean
the form containing no water
reduction=________ in oxidation number?
decrease
oxidation=________ in oxidation number?
increase
123FHOC - what do these all mean in terms of oxidation state
oxidation sates:
- group 1= 1+
- group 2= 2+
- group 3= 3+
- flourine= -1
- hydrogen= +1
- oxygen= -2
- chlorine nearly always=-1 (except when bonded to oxygen)
if something is in its elemental state, what’s its oxidation state
0
what are the 7 solubility rules
- all salts of group 1 and ammonium are soluble
- all salts of nitrates, chlorates and acetates are soluble
- all salts of halides are soluble except silver(I),copper(I), lead (II) sulfate and strontium sulfate
- All salts of sulphate are soluble except for barium sulfate, lead(II) sulfate, and strontium sulfate
- All salts of carbonate, phosphate and sulphite are incsoluble, except those from point 1.
- All oxides and hydroxides are insoluble except those from group 1, calcium, strontium and barium
- all salts of sulfides are insoluble except those from group 1 and 2** elements and of ammonium.
salts are _____, _____ and _____
sulfates, chlorides and nitrates
what is the definition of relative atomic mass
the weighted mean mass of an atom of an element compared with one twelfth of the mass of an atom of carbon-12
what id relative isotopic mass
the mass of an atom of an isotope compared with one twelfth of the mass of an atom of carbon-12
what is a mole
the amount of any substance containing as many particles as there are carbon atoms in exactly 12g of the carbon-12 isotope
what does the avogadro constant represent
the number of atoms per mole of the carbon 12 isotope.
what is mass number the same as
relative atomic mass
what type of reaction has the greatest atom economy
addition
how do you calculate mols of ions
same as how you would calculate mols of atoms (using Avogadro’s constant)
state the similarities and differences between the atomic structures of isotopes
- same amount of protons and electrons
- different number of neutrons
how could you reduce percentage error when weighing something
use a balance weighing more decimal places
how do you calculate percentage error
uncertainty( +- (you may have to x by 2 eg if weighed twice)/ measurement from apparatus x100
EXPLAIN one advantage of a high atom economy
more sustainable/ less waste product
explain one advantage of a high percentage yield
less waste of reactants
3 reasons for a need for a high atom economy
- reduces production of unwanted product
- makes this process more sustainable
- in this reaction, water is the only unwanted process so green
