alkanes

Question 1

general formula for alkanes

Answer 1

CnH2n+2

Question 2

how are sigma bonds formed?

Answer 2

overlap of 2 orbitals, for each bonding atom

Question 3

what are the bond angles of alkanes?

Answer 3

109.5

Question 4

what is the shape from alkanes?`

Answer 4

tetrahedral

Question 5

explain the effect of chain length of boiling point.

Answer 5

• as the chain length increases
• surface area increases
• greater surface area of contact
• London forces increases
• more energy is needed to overcome the forces
• boiling point increases

Question 6

explain the effect of branching on boiling point

Answer 6

• more branching
• decrease in surface area of contact
• London forces increases
• less energy is needed to overcome the forces
• boiling point decreases

Question 7

explain why alkanes do not react with most common reagents.

Answer 7

• sigma bonds are strong
• C-C bonds are non- polar
• C-H bonds are non- polar
• electronegativity of carbon and hydrogen are similar

Question 8

write the equation for the complete combustion of alkanes

Answer 8

alkane + oxygen -> carbon dioxide + water

Question 9

write the equation for the incomplete combustion of alkanes

Answer 9

alkane + oxygen -> carbon monoxide/ carbon + water

Question 10

explain the limitations of radical substitution in organic synthesis

Answer 10

• further substitution resulting in a mixture of compounds being formed
• Substitution at different positions in a carbon chain