20A.1 Flashcards
what is the traditional method of compound analysis
finding the empirical formula followed by the molecular formula, and then the functional groups present
how can we find the empirical formula of a compound
by finding the percentage composition by mass of the elements and then dividing them by their Ar and then ratio them out by dividing with the lowest number until you gain a whole number ratio
how do we find the molecular formula from the empirical formula
by taking the known molecular mass of the molecular formula and diving it up by the empirical formula mass to get a whole number ratio that you would multiple through in the empirical formula
combustion analysis is used to find
percentage composition of a compound
how do we use combustion analysis to find percentage composition
we burn the compound in excess dry oxygen, then the mass of the water and oxygen are measured.
so for a compound that contains water, oxygen, and hydrogen only we can work out:
mass of carbon dioxide(given) to mass of carbon to them percentage mass of carbon within CO2
mass of water(given) to mass of hydrogen to percentage mass of hydrogen within water
then percentage mass of oxygen by= 100 - (%carbon + % hydrogen)
to find the structural formula from the molecular formula you need to
identify the functional groups in the in the compounds
what are all the test that identify the functional compound that we need to know
page 261 FOCUS ON THEM DONT BE LAZY PLEASE A* INSHALLAH
what does mass spectrometry help us with
it helps us to determine the accurate relative molecular mass of a compound (from the M/z peek), and the fragmentation present helps us suggest possible groups that can be in the compound
how does infrared spectroscopy help us
allows us to identify particular functional groups and features in an organic compound
how does the 13 carbon NMR spectrum help us
it allows us to identify the number of different environment (as well as the environment itself) for carbon atoms present in the compound
how does the proton NMR spectrum help us
it allows us to identify groups of hydrogen atoms in a compound within the same environment, and the splitting pattern allows us to identify the number of hydrogens on the adjacent carbon atom
Practice questions
262 - 263
