Post by Admin on Nov 24, 2016 10:11:06 GMT
Acids & Bases
An acid is a substance that turns blue litmus paper to red.
Acids can be strong (e.g. hydrochloric acid, sulfuric acid) or weak (e.g. vinegar, lemon juice).
A base is a substance that turns red litmus paper to blue.
Strong bases include sodium hydroxide and potassium hydroxide, weak bases include soap and baking soda.
Bases can also be called alkalis.
pH & Indicators
The pH scale is a scale ranging from 0 to 14. It is used to measure how strong an acid or base is.
Acids have a pH less than 7, bases have a pH above 7 and a substance with a pH of 7 is neutral.
pH can be measured using universal indicator paper. The colour of the paper gives the pH of the substance.
Acid-Base Reactions
Acids and bases react to form a salt and water. This is known as a neutralisation reaction. The hydrogen in the acid is replaced with a metal from the base.
e.g. HCl + NaOH -> NaCl + H2O.
Acids and bases are neutralised in a titration reaction. The acid is placed in a burette, and the base is placed in a conical flask.
Acids and carbonates react to form a salt, water and carbon dioxide.
e.g. 2HCl + CaCO3 -> CaCl2 + H2O + CO2
An acid is a substance that turns blue litmus paper to red.
Acids can be strong (e.g. hydrochloric acid, sulfuric acid) or weak (e.g. vinegar, lemon juice).
A base is a substance that turns red litmus paper to blue.
Strong bases include sodium hydroxide and potassium hydroxide, weak bases include soap and baking soda.
Bases can also be called alkalis.
pH & Indicators
The pH scale is a scale ranging from 0 to 14. It is used to measure how strong an acid or base is.
Acids have a pH less than 7, bases have a pH above 7 and a substance with a pH of 7 is neutral.
pH can be measured using universal indicator paper. The colour of the paper gives the pH of the substance.
Acid-Base Reactions
Acids and bases react to form a salt and water. This is known as a neutralisation reaction. The hydrogen in the acid is replaced with a metal from the base.
e.g. HCl + NaOH -> NaCl + H2O.
Acids and bases are neutralised in a titration reaction. The acid is placed in a burette, and the base is placed in a conical flask.
Acids and carbonates react to form a salt, water and carbon dioxide.
e.g. 2HCl + CaCO3 -> CaCl2 + H2O + CO2