Types of chemical reaction - Coggle Diagram
Types of chemical reaction
Acids and bases
solutions of acids contain ions, and they conduct electricity
Hydrogen chloride is a gas, made of molecules. It dissolves in water to
give hydrochloric acid
In a solution of hydrochloric acid, all the molecules of hydrogen chloride have become ions, but in weak acids, only some of the molecules have become ions. For example, ethanoic acid
In solutions of strong acids, all the molecules become ions.
In solutions of weak acids, only some do
When acids react with metals, bases and carbonates, a salt is produced. Salts are ionic compounds. Sodium chloride, NaCl, is an example.
The metal drives the hydrogen out of the acid, and takes its place: it displaces hydrogen
When reacting with a base, it gives only a salt and water. Metal oxides and hydroxides are bases. Alkalis are soluble bases
By definition, a neutral solution is a solution that has a pH of 7. It is neither acidic (pH < 7) nor basic (pH > 7), but right in the middle
pH and indicators
pH indicators exist as liquid dyes and dye-infused paper strips. They are added to various solutions to determine the pH values of those solutions.
Whereas the liquid form of pH indicators is usually added directly to solutions, the paper form is dipped into solutions and then removed for comparison against a color/pH key
Formation of salts
A salt is an ionic compound that is formed when an acid and a base neutralize each other. While it may seem that salt solutions would always be neutral, they can frequently be either acidic or basic.
Oxidation and reduction always
take place together
If a substance loses electrons during a reaction, it has been oxidised.
If it gains electrons, it has been reduced.
You can use half-equations to show the electron transfer in a reaction. One half-equation shows electron loss, and the other shows electron gain
Extraction of metals
After mining an ore, the next step is to remove or extract the metal from it. How you do this? It depends on the metal’s reactivity.
The most unreactive metals – such as silver and gold – occur in their ores as elements. . All you need to do is separate the metal from sand and other impurities. This is like removing stones from soil. It does not involve chemical reactions
The ores of all the other metals contain the metals as compounds. These have to be reduced, to give the metal
carbon will react with oxides of metals less
reactive than itself, reducing them to the metal
The compounds of the more reactive metals are very stable, and need electrolysis to reduce them. This is a powerful method, but it costs a lot because it uses a lot of electricity
Extraction of iron requires the use of a blast furnace. It is an oven shaped like a chimney, at least 30 metres tall
A mixture called the charge, containing the iron ore, is added through the top of the furnace. Hot air is blasted in through the bottom. After a series of reactions, liquid iron collects at the bottom of the furnace.