Amount of a substance Flashcards
How many atoms are in one mole
6.02 x10^23
moles equation from mass
moles = mass/mr
what is molar mass
mass per mole
moles from conc
mol = conc x vol
What is empirical formula
the simplest whole number ratio of atoms of each element in a compound
Relative molecular mass
The mass of a molecule compared to 1/12 of carbon 12 (sum of the ar
relative formula mass
the mass of a formula unit compared to 1/12 of carbon 12
What is the water of crystallisation
water that is part of the crystalline structure of a salt. this is represented by a formula of a salt with a .h20
This can be evaporated leaving an anhydrous crystal
experiment to find the formula or a hydrated salt
- weigh an empty crucible
-add the hydrated salt and weigh both the crucible and salt - heat the crucible abstaining the hydrated salt gently for 1 mon and then strongly for a further 4
-leave to Coll and re-weight the crucible - calculate the mol of anhydrous salt formed
-calculate the mol of water that has been evaporated
-find the smallest whole number ratio
What is a standard solution
a solution of a known conc
How do you prepare a standard solution
add a known number of moles of solute into a a known number of moles of solvent
moles in gass volumes
1 mol = 24dm3w
what is the ideal mass equation
pV = nRT
pressure x volume = amount of moles x Ideal mass co-nstant (8.31) x temperature (kelvin)
what is stoichiometry
the ration of balancing numbers in an equation
What is percentage yield?
actual yield / theoretical yield
