Organic Chemistry: Alkanes Flashcards
1
Q
what are alkanes?
A
saturated hydrocarbons containing single C-C bonds and C-H bonds as ó(sigma) bonds
2
Q
what are sigma bonds?
A
overlap of orbitals directly between the bonding atoms, sigma bonds have free rotation
3
Q
how does the chain length of an alkane affect boiling point?
A
- increase in carbon chain length = increase in boiling point
- greater surface area of contact = stronger London forces
- more energy required to overcome these intermolecular forces
4
Q
how does the branching of an alkane affect boiling point?
A
- more branching = lower boiling point
- less surface area of contact = weaker London forces
- less energy is required to overcome these intermolecular forces
5
Q
why do alkanes have low reactivity with many reagents?
A
- high bond enthalpy
- very low polarity of the sigma bonds present
6
Q
what is a danger of incomplete combustion of alkanes?
A
carbon monoxide which is a toxic gas
7
Q
what is the complete combustion of alkanes used for?
A
used in fuels
8
Q
what is the shape of alkanes?
A
- tetrahedral shape, 109.5 around each carbon atom in alkanes
9
Q
what are the reactions of alkanes?
A
- radical substitution
- combustion
