Amount of substance Flashcards
What is relative atomic mass?
A, is the weighted average mass of an atom of an element, taking into account its naturally occurring isotopes, relative to 1/12 relative atomic mass of an atom of carbon-12.
What is relative molecular mass?
Mr, of a molecule is the mass of that molecule compared to 1/12 the relative atomic mass of an atom of carbon-12.
What is avogadro constant?
is the number of atoms in 12 g of carbon-12.
What is a mole?
The amount of substance thar contains 6.022 x 10(23) particles
What does concentration of a solution tell us?
how much solute is present in a known volume of solution
How to work out concentration in mol/dm(-3)?
concentration =
volume V (dm^3)
How do you work out the number of moles in a solution?
number of moles in a solution (n) =
1000
What are the 3 gaseous laws?
Boyle’s law
Charles’ law
Gay-Lussac’s Law
What does Boyle’s law state?
pressure (P) x volume (V) =constant
What does Charles’ law state?
Volume (Inversely proportional) temperature T
volume (V)
——————— = constant
tempreture (T)
What does Gay-Lussac’s law state?
Pressure (Inversly Proportional) Temperature
pressure (P)
——————— = constant
temperture (T)
What is the ideal gas equation?
pressure (Pa) x volume(m^3) = number of moles (n) x gas constant (J K^-1 mol^-1) x Tempreture (K)
How you carry out a titrations?
1) Fill a burette with the acid of known concentration
2) Accurately measure an amount of the alkali using a calibrated pipette
and pipette filler
3) Add the alkali to a conical flask with a few drops of a suitable indicator
4) Run in acid from the burette until the colour just changes, showing that the solution in the conical flask is now neutral
5) Repeat the procedure, adding the acid dropwise as you approach the end point, until two values of the volume of acid used at neutralisation are the same, within experimental error
Equation for atom economy?
Atom economy =
mass of desired product
————————————- X 100
total mass of reactants
What does atom economy tell us?
in theory how many atoms must be wasted in a reaction.
