moles 1 and organics Flashcards
What is meant by the term “relative atomic mass”?
The average mass of all isotopes of an element, taking into account their abundance
RFM is?
relative formula mass = use periodic table and add up mass numbers to find rfm for compound
Equation linking mass rfm and moles?
mass = rfm x moles
To find the percentage mass of an element in a compound do
Element’s mass in compound/RFM of compound x 100
what is water crystallisation
when salt forms crystals a particular amount of water gets trapped in the crystals = trapped water is water crystallisation
equation for percentage yield
PERCENTAGE YIELD = ACTUAL YIELD/THEORETICAL YIELD X 100
What might the reasons be for not making the theoretical yield (100% yield)?
Incomplete reaction
Loss of products
Impure reactant
Why do we deliberately put in too much of one reactant
the aim of this is to make sure that all of the other reactant(s) gets used up.
define molecular formula
only shows how many carbon+hydrogen atoms there are
define empirical formula
shows simplest whole number ratio of carbon to hydrogen
define displayed formula
diagram showing positions of every atom + bond
define functional group
The C with all the dashes around it - determined all the chemical properties of a compound
define structural formula
shows structure of molecule in on line read from left to right e.g CH3, CH2, CH2, CH3
define homologous series
a family of molecules with similar chemical reactions and same general formula
define hydrocabon
compound made of hydrogen and carbon only
what is crude oil
a mixture of hydrocarbons, comes from oil reserved underground, used as fuel, non renewable - could cause environmental problems e.g microplastics/combustion
What are alkanes
Saturated hydrocarbons where all carbon atoms have 4 single covalent bonds
What is the general formula for alkanes
CnH2n+2
What are alkenes
Unsaturated hydrocarbons = they have a double carbon bond c=c
5 common alkanes
Methane - CH4
Ethane - C2H6
Propane - C3H8
Butane - C4H10
Pentane - C5H12
What is the general formula for alkenes
CnH2n
4 common alkenes
Ethene = C2H4
Propene = C3H6
Butene = C4H8
Pentene = C5H10
what can happen in change isomerism
the position of the double c bond can change = position isomerism
Why do methane ethane and propane have no isomers (same molecular formula different structural formula)
their chains are too short
