combustion Flashcards
fuel
A chemical substance from which stored energy can be transferred usefully to make things happen.
Fuel Cell
Used in hydrogen-powered vehicles, releasing energy from hydrogen.
Fuel Cell Word Equation
Hydrogen + oxygen → water
Reactants
The starting substances- on left of word equation.
Products
The new substances made- on right of word equation.
Combustion
Burning, usually in air. The reaction gives out energy which is transferred to the surroundings by heating or light.
Fossil Fuels
Fuels formed from living organisms that died millions of years ago- petrol, diesel
Hydrocarbons
Only contain carbon and hydrogen atoms- petrol, diesel
Combustion of Hydrocarbons
The carbon and hydrogen atoms react with oxygen. The carbon reacts to form carbon dioxide.
Carbon Dioxide
Carbon dioxide will turn limewater cloudy.
Oxidation
Reacting with oxygen.
Oxide
Compound formed by oxidation.
Metal Oxides
Formed when metals react with oxygen.
metal + oxygen → metal oxide
Conservation of Mass
Mass is never gained or lost in a chemical reaction. The atoms in reactants just rearrange to form the products, no new atoms are made and none disappear.
Heating Zinc in Air
Forms a white powder zinc oxide. The mass will appear to increase because the zinc has combined with the oxygen in air.
Gas Products
If the product is a gas it may escape and make it seem like the mass has decreased.
Phlogiston
A substance scientists used to think explained why things burned that was then proven not to exist.
Exothermic
A reaction that releases energy that we can feel as heat- combustion
Thermometer
Used to measure a change in the temperature.
Fire Triangle
Three factors allow combustion to
occur.
Putting Out a Fire
You must remove at least one of the three factors.
Fire Extinguishers
Work by cooling a fire or stopping oxygen getting to the fuel.
Oil Fire
Water will sink through the oil and turn to steam making the fire spread out. Use foam or a fire blanket to keep oxygen away.
Electrical Fire
Water conducts electricity so you may get a serious shock. Turn off the electricity and use a powder or carbon dioxide extinguisher.
Complete Combustion
Carbon burns in plenty of air only forming carbon dioxide.
Incomplete Combustion
Not enough oxygen for all the carbon to react with.
Products of Incomplete Combustion
carbon dioxide- linked to global warming
carbon monoxide- poisonous gas
soot- damage lungs and trigger asthma
Impurities
Small amounts of other substances in fuels.
Sulfur Dioxide
Formed when hydrocarbons have a sulfur impurity.
Nitrogen Oxide
Formed by high engine temperatures causing nitrogen and oxygen in air to react.
Catalytic Converter
Found in cars to react carbon monoxide with more oxygen forming carbon dioxide. Also breaks down nitrogen oxides.
Pollutants
Something that can harm living things and damage the environment.
Acid Rain
Sulfur dioxide and nitrogen oxides rise into the air and dissolve in water vapour. The rain is now more acidic.
Controlling Acid Rain
Neutralisation reactions used to remove acidic gases from chimney smoke. Acidic soil /water can be neutralised by adding calcium carbonate.
Greenhouse Gases
Trap energy from the Sun in the atmosphere e.g. carbon dioxide
Greenhouse Effect
Energy trapped by greenhouse gases is transferred back to the Earth’s surface causing it to warm up.
Earth’s Temperature Over Time
The temperature of the Earth has fluctuated over time it is rising rapidly now though.
Global Warming
Increase in global temperature due to more greenhouse gases in the air and the greenhouse effect.
Climate Change
Resulting from global warming- changes to weather patterns, more storms, flood, droughts, etc.
Evidence
There is now lots of evidence for global warming. average temperatures are increasing and ice caps are melting.
