Chem I - Crude oil, hydrocarbons and alkanes

Question 1

Crude oil

Answer 1

Crude oil is a dark and thick liquid that is a mixture of different length hydrocarbons.

Question 2

How was crude oil formed?

Answer 2

Microscopic plants & animals die and fall to the seabed.
Layers of sand and mud fall on top.
High pressure and high temperatures cause oil to form.
Oil obtained by drilling.

Question 3

How is kerogen formed?

Answer 3

Kerogen is formed from marine algae which turns into oil and gas when heat and pressure is applied.

Question 4

Features of alkanes

Answer 4

All contain Carbon and Hydrogen.
Only have single bonds.
Names all end in -ane

Question 5

Fractional distillation

Answer 5

Crude oil heated to vapour before entering the column.
Long chain hydrocarbons condense at the bottom of the tower where its hotter
As the hydrocarbon move up the column, they reach their boiling point and are collected as a liquid.
Fractions collected as liquids on different levels.
Short chain hydrocarbons condense and are piped out on the top of the column.

Question 6

Formula for alkanes

Answer 6

C6H [2n+2)

so C6H14

Question 7

Formula for alkenes

Answer 7

C6H [2n]

so C6H4

Question 8

Word equation for alkanes

Answer 8

heat
Large alkane ——–> alkene + small alkanes
catalyst

Question 9

Interpreting a chromatogram

Answer 9

A pure substance produces one spot on the chromatogram.
Impure substances and mixtures produces 2 or more spots on the chromatogram.
The further up the paper, the more soluble the substance.

Question 10

Crude oil is an important source of…

Answer 10

Fuels such as petrol, diesel, kerosene and heavy fuel oil.

Feedstock for the petrochemical industry

Question 11

Why are hydrocarbons classified as a fuel?

Answer 11

They release energy when burned