chapter 3- Amount of substance Flashcards
(15 cards)
what is one mole equal to
exactly 12g of c12
what is the equation for working out moles
mass/ mr
what is avogadros number
6.02x10^23
you use it by multplying moles by this
what is empirical formula
the simple whole number ratio of atoms of each element present in a compound
how do you work out empirical formula
find the moles of the compounds by doing mass/mr
then select the element with lowest moles and divide the rest by it
this is now your empirical formula
how do you calculate molecular formula
do the relative molecular mass divided by the Mr of the empirical formula
then multiply the empirical formula by your answer
what is a hydrated compound and what is a anhydrous
hydrated- contains water bonded into the structure
anhydrous- no water
. this dot means the amount of water
how do you calculate formula of hydrated salts
step 1- calculate the amount of anhydrous Na2SO4 and H2O
step 2- calculate the ratio of the amounts and the formula
what is concentration
the amount in moles of a dissolved substance in 1 dm3 of solution
what is the equation for concentration
moles=conc x volume
remember volume has to be in dm3
what is the equation for molar gas volume
moles= volume/ 24.0
what is the ideal gas equation
pV=nRT
p= pressure v= volume
n= moles t=temp(in k)
r= gas constant = 8.314mol-1k-1
how can the ideal gas equation be used to calculate relative molecular gas of a volatile liquid
weighted then heated above its known boiling point
the volume of gas is measured and pressure is recorded
what is the equation for atom economy
atom economy= sum of molar mass of desired/sum of molar masses of all products
what is the equation for percentage yeild
percentage yeild= actual yeild/theoretical yeild x 100
