alkanes

Question 1

Organic compound D is formed by subsititution of all the H atoms in butane by Cl atoms write the equation for the formation of compound D from butane use molecular formula

Answer 1

C4H10 + 10Cl2 -> C4Cl10 +10HCl

Question 2

What is meant by the term structural isomer and explain the trend in boiling points with increased branching (4)

Answer 2

• different structural formula and same molecular formula
• boiling point decreases with more branching
• more branching gives less surface contact and fewer london forces
• less energy to break london forces

Question 3

Compounds A, B and C all react with chlorine in the prescemce of ultraviolet radiation to form organic compounds with the formula C5H11Cl name the mechanism of this reaction

Answer 3

radical substitution

Question 4

2 chloropropanoic acid can be made by reacting propanoic acid with clorine in a radical substitution reaction state the conditions for the reaction

Answer 4

• ultravoilet radiaton

Question 5

write overall equation for propanoic acid and chlorine

Answer 5

CH3CH2COOH +Cl2 -> CH3CHClCOOH + HCl

Question 6

Why is the intitiation stop of a radical substitution an example of homolytic fission (1)

Answer 6

• one electron from the bond pair goes to each atom/chlorine/radical

Question 7

At room temperature and pressure the first four members of the alkanes are all gases but the first ofur alchols are all liquid
explain this difference in terms of intermolecular forces (2)

Answer 7

• alchols have hydrogen bonds and london forces
• hydrogen bonds are stronger than london forces in alkanes

Question 8

Construct and equation for the complete combustion of octane (1)

Answer 8

C8H18+12.5O2->8CO2+9H2O

Question 9

What is meant by the term homologous series (2)

Answer 9

same functional group
each successive member differeing by Ch2

Question 10

State the general formula for cycloalkanes

Answer 10

CnH2n

Question 11

The C-C-C bond angles in cyclohexane are 109.5 state and explain the shape around each carbon atom in cyclohexane

Answer 11

tetrahedral four bonding pairs repel

Question 12

Explkain why radical substitution likely to produce a mixture of organic products

Answer 12

substitution can replace any H stom/multiple substitution

Question 13

Explain the potential danger of incomplete combustion (1)

Answer 13

CO is toxic

Question 14

Describe how a sigma bond forms

Answer 14

overlapping or orbitals directly between the bonding atoms

Question 15

State the bond angle and shapee around each carbon atom of the C=C double bond in propene

Answer 15

12
triagonal planar