QUANTITATIVE CHEMISTRY Flashcards
what is the conservation of mass
in a chemical reaction, atoms are not created or destroyed, just rearranged so total mass before is the same as after
when a metal forms a metal oxide why does the mass increase
atoms from gaseous oxygen have been added
when an acid reacts with a metal why does the mass decrease
a gas is produced and escapes
what is relative formula mass
the sum of the relative atomic masses of each atom in a substance
what is a mole
mass of a substance that contains 6.03 x10 23 particles
which formula is used to calculate the number of moles from mass and Mr
moles = mass/ Mr
what is a limiting reactant
the reactant that is completely used up in a chemical reaction
what is the unit for concentration
g/dm3 or mol/dm3
formula to calculate conc from mass and volume
conc = mass/ volume
how can you convert a volume reading in cm3 to dm3
divide by 1000
if the amount of solute in a solution increases what happens to its conc
increases
what is the yield of a reaction
mass of a product obtained from the reaction
what is the theoretical yield of a reaction
maximum mass of the product that could have been produced
why is the actual yield always less than the theoretical yield
- reaction may be reversible
- some of the product can be lost on separation
- unexpected side reactions between reactants
what is the percentage yield
actual yield as a proportion of the theoretical yield
