Functional groups and homologous series Flashcards
a functional group is a molecule or group of atoms which
gives the compound some distinctive and predictable properties
what does the COOH functional group give as a property?
a sour and acidic taste
homologous series have similar chemical and physical properties that show a
gradation- gradual change from one to the next
the organic compounds that are mainly used as fuels are
alkanes
which organic compound is a common fuel?
alkanes
alkanes do not contain
a functional group
what makes alkanes a homologous series?
they differ by CH2 for each next member
the five types of formula are
molecular, empirical, displayed, structural, skeletal
what type of formula can we use for homologous series?
general formulae
in general formulae, n represents
the number of carbon atoms, but excluding any in the functional group
what is the general formula for carboxylic acids?
Cn H2n+1 COOH
the general formula for alkanes is
CnH2n+2
the general formula for alkenes is
CnH2n
the general formula for halogenoalkanes is
CnH2n+1 X
the general formula for alcohols is
CnH2n+1 OH
all alkanes form………as products when burned in air
carbon dioxide and water
the commonest alkanes is
methane
the equation for the complete combustion of methane is
CH4 + 2O2 = CO2 + 2H2O
the boiling point of alcohols ……….. as you go down the homologous series?
increases
the boiling point of alcohols increases as gradation because
the carbon chain length increases, so more energy is required to break all the carbon-carbon bonds in the chain
in molecular models, what colour are carbon, hydrogen and oxygen?
carbon is black, hydrogen is white and oxygen is red
