Fuels Flashcards

A compound that contains carbon and hydrogen only.

False. It contains oxygen as well as carbon and hydrogen, so it is not a hydrocarbon.

A complex mixture of hydrocarbons, whose molecules have carbon atoms in chains or rings. It is a finite resource.

It is a source of fuels and of feedstock for the petrochemical industry.

The crude oil is heated to a vapour and fed into a column that is hot at the bottom and cooler at the top. Each fraction condenses at the height matching its boiling point range: higher boiling points condense lower down.

The molecules are larger/longer (more carbons), so there are stronger intermolecular forces between them.

Fuel for aircraft (jets).

Fuel for some cars and for trains (also lorries, tractors).

Fuel for large ships and in some power stations.

Surfacing roads and roofs.

They have the same general formula, and neighbouring compounds differ by $CH_2$ . (Also: same functional group, similar chemical properties, a trend in physical properties.)

$C_nH_{2n+2}$ — with $n = 4$ this gives $C_4H_{10}$ .

They differ by $CH_2$ , and they have the same general formula $C_nH_{2n+2}$ (both alkanes).

Carbon dioxide and water, and energy is given out (the reaction is exothermic).

There is insufficient oxygen to oxidise all the carbon to carbon dioxide.
e.g. $2CH_4 + 3O_2 \rightarrow 2CO + 4H_2O$

It reacts with haemoglobin in the blood, stopping oxygen being carried, so less oxygen reaches the brain. It is colourless and odourless, so hard to detect.

It can aggravate asthma/respiratory problems, and it makes buildings dirty.

The sulfur impurity is oxidised to sulfur dioxide, which dissolves in rain water/clouds to form sulfuric acid.

It kills fish in lakes and kills trees. (It also damages buildings and causes breathing problems.)

They are acidic and toxic, and they lead to acid rain, which damages buildings and kills plants.

Sulfur dioxide (from the sulfur impurity) and carbon dioxide.

Burning it produces only water, so no carbon dioxide, carbon monoxide or sulfur dioxide; the supply can be renewable (made from water).

It is hard to store and transport (very flammable gas, stored under pressure), and there are few filling stations; energy from fossil fuels is often used to make it.

Petrol, kerosene and diesel oil from crude oil; methane from natural gas.

It is used up much faster than it is formed, so the supply is finite and cannot be replaced.

Breaking down larger, saturated hydrocarbon molecules (alkanes) into smaller, more useful ones, some of which are unsaturated (alkenes).

The supply of long-chain fractions is greater than the demand, while demand for short-chain fuels such as petrol is high; cracking also makes useful alkenes.

False. Some products are unsaturated alkenes, such as $C_2H_4$ .

Fuel for cars.

Domestic heating and cooking.

The engine gets very hot, and at these high temperatures nitrogen and oxygen from the air drawn in react with each other.

It increases. Longer molecules have stronger intermolecular forces between them, so more energy is needed to overcome these forces.

Key Concepts in Chemistry

States of Matter & Mixtures

Chemical Changes

Extracting Metals & Equilibria

Groups in the Periodic Table

Rates of Reaction & Energy Changes

Fuels & Earth Science