15.2 Reactions Of Alkanes Flashcards
What is the reactivity of alkanes
Alkanes are generally unreactive compounds
Why are alkanes generally unreactive
There is a very small difference in electronegative between carbon and hydrogen. Therefore they are non-polar, they have no δ+ charge to attract nucleophiles neither do they have areas of high electron density to attract electrophiles.
What are some reactions that alkanes would take place in
Alkanes react with oxygen in combustion reactions and also undergo substitution by halogens in sunlight.
Alkanes are often used as fuels for
Generating electricity in power stations
To heat our homes and cook our food
To provide energy needed in industrial processes
To provide fuel for vehicles
Chemical equation for combustion of alkanes
Alkane+oxygen—>carbon dioxide+ water
What happens when petrol or diesel is burned inside the car engine
There is only a limited supply of oxygen. Under these conditions not all the carbon in hydrocarbon fuel is fully oxidised to CO2. Some of the carbon is only partially oxidised to carbon monoxide gas. This is called incomplete combustion.
Why is carbon monoxide harmful
It bonds with haemoglobin in your blood. The haemoglobin molecules can then no longer bond to oxygen so cannot transport oxygen around your body.
What will victims of carbon monoxide poisoning fell
They will feel dizzy then lose consciousness. If not removed from the toxic gas, the victim will die
What does carbon monoxide smell like
It is odourless
Apart from releasing CO, what are some other dangerous gases that car engines release
NO and NO2- and other acidic nitrogen oxides.
What are disadvantages of acidic nitrogen oxides being released to the environment
They contribute to the problem of acid rains
Acid rains can kill trees and aquatic animals in lakes.
Acid rains erodes limestone buildings and statues
Acid rain corrodes metals such as iron
What causes nitrogen to be oxidised
The very high temperatures of car engines
The chemical equation first the production of Nitrogen oxide are
N2(g)+O2(g)<—> 2NO(g)
2NO(g)+O2(g)<—>2NO2(g)
What are volatile Organic Compounds (VOCs)
Unburnt hydrocarbons released by car engines into the air
What are some harms of VOCs
Some of there are carcinogens(can cause cancer)
