ACIDS AND BASES

Acids  Acidic solutions contain water and hydrogen ions (H+)

Acids  Acidic solutions contain water and hydrogen ions (H+)  When dilute acidic solutions react, it is the hydrogen ions that are involved in the reaction.

Acids  Acidic solutions contain water and hydrogen ions (H+)  When dilute acidic solutions react, it is the hydrogen ions that are involved in the reaction.  Common acids are: - Hydrochloric acid (HCl)

Acids  Acidic solutions contain water and hydrogen ions (H+)  When dilute acidic solutions react, it is the hydrogen ions that are involved in the reaction.  Common acids are: - Hydrochloric acid (HCl) - Nitric Acid (HNO 3 )

Acids  Acidic solutions contain water and hydrogen ions (H+)  When dilute acidic solutions react, it is the hydrogen ions that are involved in the reaction.  Common acids are: - Hydrochloric acid (HCl) - Nitric Acid (HNO 3 ) - Sulfuric Acid (H 2 SO 4 )

Acids  Acidic solutions contain water and hydrogen ions (H+)  When dilute acidic solutions react, it is the hydrogen ions that are involved in the reaction.  Common acids are: - Hydrochloric acid (HCl) - Nitric Acid (HNO 3 ) - Sulfuric Acid (H 2 SO 4 ) - Citrus fruits are acidic, as well as carbonated drinks (like coke).

Bases  Bases are substances that neutralise acids by forming water and a salt.

Bases  Bases are substances that neutralise acids by forming water and a salt.  Common bases are: - Sodium Hydroxide (NaOH)

Bases  Bases are substances that neutralise acids by forming water and a salt.  Common bases are: - Sodium Hydroxide (NaOH) - Calcium hydroxide ( Ca(OH) 2 ) or limewater

Bases  Bases are substances that neutralise acids by forming water and a salt.  Common bases are: - Sodium Hydroxide (NaOH) - Calcium hydroxide ( Ca(OH) 2 ) or limewater - Ammonia solution (NH 3 )

Bases  Bases are substances that neutralise acids by forming water and a salt.  Common bases are: - Sodium Hydroxide (NaOH) - Calcium hydroxide ( Ca(OH) 2 ) or limewater - Ammonia solution (NH 3 )  Bases have hydroxide ions (OH-)

Neutral Substances  Some substances, such as salt (Sodium Chloride) dissolve in water forming solutions which are neutral.

Neutral Substances  Some substances, such as salt (Sodium Chloride) dissolve in water forming solutions which are neutral.  Pure water is neutral

The pH scale  Some acids are stronger than others; strong acids produce the highest concentration of hydrogen ions.

The pH scale  Some acids are stronger than others; strong acids produce the highest concentration of hydrogen ions.  Strong bases produce high concentrations of hydroxide ions.

The pH scale  Some acids are stronger than others; strong acids produce the highest concentration of hydrogen ions.  Strong bases produce high concentrations of hydroxide ions.  The same applies for weak acids/weak bases having low concentrations of particular ions.

The pH scale  Some acids are stronger than others; strong acids produce the highest concentration of hydrogen ions.  Strong bases produce high concentrations of hydroxide ions.  The same applies for weak acids/weak bases having low concentrations of particular ions.  The pH scale is used to measure how acidic or basic a solution is.

The pH scale  Acidic solutions have pH of less than 7

The pH scale  Acidic solutions have pH of less than 7  Basic solutions have pH of more than 7

The pH scale  Acidic solutions have pH of less than 7  Basic solutions have pH of more than 7  Neutral solutions are 7

The pH scale  Acidic solutions have pH of less than 7  Basic solutions have pH of more than 7  Neutral solutions are 7  Red and blue litmus paper can be used to indicate whether the solution is an acid or a base.

The pH scale  Acidic solutions have pH of less than 7  Basic solutions have pH of more than 7  Neutral solutions are 7  Red and blue litmus paper can be used to indicate whether the solution is an acid or a base.  Red – turns blue in a base  Blue – turns red in an acid

The pH scale  Pour 1cm of solution into your 5 test tubes  Using red or blue litmus paper, drop the paper into the test tubes and see what colours they change to.  Write down what solution is an acid or base

pH scale  Using your solutions from before…  Add universal indicator to each of your solutions and see what number pH they are.  Write it down in your books.