quantatative chemistry Flashcards
what is the relative atomic mass(ar)
average mass of all isotopes of an element
what is relative formula mass
total relative atomic mass of all atoms in a compound
what is mole
amount of substance that contains 10 tothe power of 23 particles
-eg 1 mole of o2 weighs 32 g
moles mass mr equation
moles=mass/mr or mass=moles x mr
what is the exception to the law of conservation of mass
gas may escape so scale cant weigh all the reactants considering it is an open system
why are reactants called limiting
as they limit how much product can be produced
what does burned in air mean and suggest about the products of the reaction
we can assume the oxygen is in excess so other reactant would be limiting
what is dm3 =to
1000cm3
concentration mass and volume equation
mass(g) = conc(dm-3) x vol(dm3)
volume of gas/moles and 24 equation
vol(dm3)=moles x 24
what is atom economy
the % of reactants going to form the desired product
atom economy equation
mr of desired products/mr of all reactants
x100
what is the atom economy when there is only 1 product
as there are no waste products it is 100% to our desired products
why is atom economy important to consider
1)less profit if most reactants are turned to waste products as raw materials are expensive
2)less sustainable to use large amounts of reactants to produce small amounts of products
3)waste products can damage environment and are expensive to get rid of
what are 2 ways we can counter loss of atom economy
use more efficient reactions
find use for waste products
