quantative chemistry Flashcards
what’s the conservation of mass
atoms cannot be created or destroyed , mass is always conserved
what happened if there was a decrease in mass
one of the products was a gas so it escaped from an unsealed container
what happens when there is an increase in mass
a gas from the air is a reactant therefore mass adds on
What is the equation for moles
moles = mass/ Mr
how to work out percentage mass
Ar of element X number of atoms of THAT ELEMENT / Mr of compound X 100
what is avagadros constant
6.02 x 10 ^23
what is a limiting reactant
the reactant that gets completely used up
how do you work out concentration
concentration = moles / volume
never cuddle. vikings
number of moles
conc. volume
how do you change cm^3 into dm3
divide by 1000
what is concentration measured in
mol/dm^3
what is volume measured in
dm^3
how do you work out concentration of an unknown substance
1) work out how many moles of the known substance
2) use molar ratio to work out how many moles of unknown substance
3 use the moles to work out concentration
LOOK AT EXAMPLE IN BOOK TO MAKE IT SENSE
How do you work out atom economy
Mr of desired products/ Mr of all reactants X 100
why is it important to consider atom economy
raw materials are expensive
less sustainable
waste products
