Hydrocarbon 1 - Revision
- Created by: Ammarah123
- Created on: 17-01-18 18:41
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- Fuels and Earth Science
- Fractional Distillation
- Crude Oil
- 3 The hydrocarbons found in crude oil have their carbon atoms arranged in chains and are mostly alkanes
- Alkanes have their own general formula- Cn H2n+2
- Non- renewable resource (finite) so on day it will run out
- 4 Can be separated into fractions- Smaller and useful mixtures containing groups of hydrocarbons of similar lengths
- The different fractions are separated by fractional distillation. The oil is heated until it is turned into gas- The gases enter the fractionating column
- The longer hydrocarbons have higher boiling points (They turn back into liquids and drain of the column early on, where they are near the bottom)
- The shorter hydrocarbons have lower boiling points (They turn into liquids and drain out out much later on, near to the to top of the column where it's cooler
- 1 Main source of hydrocarbons and is used as a raw material to create lots of useful substances
- 3 The hydrocarbons found in crude oil have their carbon atoms arranged in chains and are mostly alkanes
- Crude Oil
- Pollutants
- Acid Rain
- When fossil fuels are burned, they produce sulfur dioxide. When sulfur dioxide mixes with clouds, it forms dilute sulfur dioxide which forms acid rain
- Acid rain causes lakes to become acidic and many plants and animals die as a result. It can also kill trees and damage limestone buildings
- Oxides of Nitrogen
- Can cause photochemical smog which could lead to breathing difficulties
- Acid Rain
- Hydrocarbons
- Homologous Series
- A family of molecules that have the same general formula and share similar chemical properties
- Properties of Hydrocarbons
- Big molecules have a higher boiling point because the forces are much stronger so they're harder to break
- Shorter hydrocarbons are easy to ignite because they have lower boiling points so tend to be gases at room temperature
- These gas molecules mix with oxygen which produces a gas mixture that would burst into flames if it comes in contact with a spark
- Viscosity- How easily a substance flows
- The stronger the force between hydrocarbon molecules, the harder it is for liquid to flow. Fractions containing longer hydrocarbons have higher viscosity.
- Cracking
- 1 Splitting up long chain hydrocarbons- alkane into alkenes which are more useful
- 2 Form of thermal decomposition- One substance break down into two new ones when you heat it
- 3 Involves heat (400- 700 degrees) , moderate pressures (70 atm) and a catalyst (aluminuim oxide)
- Complete and Incomplete Combustion
- Complete combustion: fuel+oxygen= carbon dioxide+water
- Incomplete combustion: fuel+oxygen= carbon monoxide+ water+carbon dioxide
- Occurs when a hydrocarbon burns in a limited supply of oxygen
- Produces carbon monoxide which is dangerous as it can combine with red blood cells and stop your blood from carrying oxygen around the body
- Tiny particles of carbon can be released into the atmosphere. When they fall back to the ground, they deposit themselves as soot.
- Soot makes buildings look dirty and can cause or worsen respiratory problems
- Homologous Series
- Fractional Distillation
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