Amount of substance Flashcards
Spectator Ions
? Ions that do not take part in the reaction
Ionic Equation
? An equation that represents ions that took part in the reaction
Relative Atomic Mass (Ar)
? Weighted average mass of all the isotopes of an element relative to C-12
Relative Molecular Mass (Mr)
? Average mass of a molecule relative to 1/12 of an atom of C-12
The mole
? the amount of substance in grams that has the same number of particles as there are atoms in 12 grams of carbon-12. (always to 1d.p)
Limiting Reagent
? Reactant that is not in excess, worked out using calculations
Atom economy
? Measure of what proportion of the products of the reaction are the desired products and how much is wasted.
Percentage atom economy
? Molecular mass of desired product/sum of molecular masses of all reactants * 100
How do you calculate atom economy?
Mass of wanted product / total mass of product *100
Titration
? A practical technique which can be used to calculate concentrations of solutions
Standard Solutions
? Solution with a known concentration
Boyle’s Law
? Pressure of a fixed mass gas under standard conditions is inversely proportional to volume. P1V1 = P2V2
Charles Law
? Volume of a fixed mass gas under standard conditions is proportional to temperature.
V1/T1 = V2/T2
Gay Lussac’s law
? Pressure of a fixed mass gas under standard conditions is proportional to volume.
P1/T1 = P2/T2
Empirical formula
? Simplest integer ratio of atoms of each element in the compound
Molecular formula
? Actual number of atoms of each element in the compound
Back titration
? Done to analyse a base (or acid) that does not react easily or quickly with an acid (or base).
The base is treated with an excess of acid and then the leftover acid titrated
Then you can work back to find out about the original base (or acid)
Why do we want a high atom economy?
As the higher the atom economy, the lesser the waste produced. This is more economically viable and uses less natural resources.
