Quantitative Chemistry (4) Flashcards
what is relative atomic mass?
(Ar/RAM)
the mass of an atom compared with carbon-12 isotope
what is the mass of the carbon-12 isotope
12
the sum
what is the relative FORMULA mass
the sum of relative atomic masses of all the atoms present in the formula of a compound
how do you find the % of an element in a compound
(RFM=relative formula mass)
mass of element in a compound
—————————————— x100
Mr/RFM of compound
the RAM of sub in g
what is the mole of a substance?
the relative atomic mass of a substance in grams
how many particles does one mole of any substance contain?
write out the triangle used for the formula that shows the relationship between the mass (in g), the Ar/RAM or Mr/RFM, and moles
(triangle between Mass, moles and Ar/Mr)
which number is the Ar/Mr
12
how many g in one kg
1000g
how many kg in one tonne
1000kg
how many g in one tonne
1000,000g
how do you work out % yield
actual yield
—————- x100
theoretical yield
maximum mass that can be obtained in a
what is the theoretical yield
the maximum mass of product that can be obtained in a chemical reaction
what is the actual yield
the mass of product actually produced in the lab at the end of the reaction
what is percentage yield
measures the proportion of products formed in a reaction and tells us how efficient a chemical process is
how do you work out the theoretical yield
use the moles calculation-
moles = mass
———
Ar/Mr
Name 3 reasons the percentage yield of the product is less than 100%
-loss by mechanical transfer from one container to another
-loss of product in separation from the reaction mixture
-reaction is reversible and may not go to completion
what is empirical formula?
formula which shows the simplest whole number ratio of atoms of each element in a compound
what is molecular formula
formula which shows the actual number of atoms of each element in a molecule
EF and RMM of compound
what two things are essential to know when working out the molecular formula
empirical formula of compound
relative molecular mass of compound
what is the method for heating copper (II) sulfate crystals
- weigh a test tube containing copper (II) sulfate crystals
- set up apparatus in the picture
- find boiling point of collected liquid
- add water
