How human activities affect the atmosphere
A reaction in which oxygen combines with another substance is called an The gain of oxygen, or loss of electrons, by a substance during a chemical reaction. reaction.
Material that is used to produce heat, like coal, oil or gas. react rapidly with oxygen, transferring The capacity of a system to do work or the quantity required for mechanical work to take place. Measured in joules (J). For example, a man transfers 100 J of energy when moving a wheelbarrow. to the surroundings by heating and by light. This type of oxidation reaction is known as burning or A reaction where fuels are burned in oxygen. Complete combustion occurs when fuels are burned in a plentiful supply of oxygen or air. . The products of combustion then enter the The layers of gases that surround the Earth. The important gases in the atmosphere are nitrogen, oxygen and carbon dioxide..
Hydrocarbon fuels
A compound that contains hydrogen and carbon only. are A substance formed by the chemical union of two or more elements. that contain hydrogen and carbon The smallest part of an element that can exist. only.
Hydrocarbon fuels can undergo Burning in a plentiful supply of oxygen or air. Complete combustion of a hydrocarbon produces water vapour and carbon dioxide. or Burning when there is a limited supply of air or oxygen., depending on the amount of oxygen available.
Complete combustion
Complete combustion of a hydrocarbon fuel happens when there is a good supply of air or oxygen. Carbon and hydrogen The smallest part of an element that can exist. in the fuel react with oxygen:
- carbon dioxide and water are produced
- energy is given out
In general:
hydrocarbon + oxygen 鈫 carbon dioxide + water
Question
Write a balanced chemical equation for the complete combustion of propane (C3H8) with oxygen (O2). Explain why the equation is balanced.
C3H8 + 5O2 鈫 3CO2 + 4H2O
Reactants: 3 脳 C, 8 脳 H, (5 脳 2 脳 O) = 10 脳 O
Products: 3 脳 C, (4 脳 2 脳 H) = 8 脳 H, (3 脳 2 脳 O) + (4 脳 O) = 10 脳 O
Incomplete combustion
Incomplete combustion happens when the supply of air or oxygen is poor. Water is still produced, but carbon monoxide and carbon are the other products. Less energy is released than during complete combustion.
Here is one possible equation for the incomplete combustion of propane:
propane + oxygen 鈫 carbon monoxide + carbon + water
C3H8 + 3O2 鈫 2CO + C + 4H2O
Notice that fewer oxygen molecules are needed to balance the equation than are needed for the complete combustion of propane.
Soot
The carbon is released as fine black A general term for a small piece of matter. For example, protons, neutrons, electrons, atoms, ions or molecules., which we can see in smoky flames, and is deposited as The fine black particles, chiefly composed of carbon, produced by incomplete combustion of coal, oil, wood, or other fuels.. Soot can cause breathing problems and it blackens buildings. It may block boilers and other appliances, or cause a fire.
Carbon monoxide
Carbon monoxide is a Poisonous. gas. It is absorbed in the lungs and binds with the The red protein found in red blood cells that transports oxygen round the body. in the The blood cell which contains the pigment haemoglobin responsible for the transport of oxygen.. This reduces the capacity of the blood to carry oxygen. Carbon monoxide causes drowsiness, and affected people may fall unconscious or even die.