Chemistry - quantitative chemistry Flashcards
relative atomic mass
same as mass number
protons + neutrons
Ar
weighted average of different mases of all isotopes of that element
mass spectrometry
- find relative atomic masses
- ions are accelerated through a magnetic field, allows mass to be detected
fragmentation pattern
used to identify molecules and their structure
percentage composition by mass
- using relative atomic mass and relative formula mass, percentage mass of element can be found
- % mass of element in compound refers to % of a certain element that is found in the compound
mole
measure of amount of substance
mole formula
no of mole = mass / mr
empirical formula
simplest ratio of various atoms
molar volume of gas
1 mol of any gas at room temperature and pressure occupoes a fixed volume of 24dm^3
concentration
measure of amount of solute in a volume of solution
titration calculation method
- reaction ratio
- calculate number of moles of known substance using n=cv
- take the reaction ratio and work out how many moles of acid will be needed to neutralise this
- know either concentration or volume of acid, use the two values to find missing value
conservation of mass
- mass conserved
- no atoms are created and no atoms are destroyed
percentage yield compare what
compare actual yield that is obtained and theoretical predicted yield
percentage yield formula
actual yield / predicted yield x 100
what kind of percentage yield is undesirable
low yield because it is not sustainable for development
