Dr Pusey

www.puseyscience.com

Acids & Bases Acids and bases are used every day

The reactions that occur with acids and bases are what make them so important

What makes an Acid? It’s all about Hydrogen ions (H+)

Remember: Ionic compounds separate into their ions when they dissolve

When an acid is in solution, it produces Hydrogen ions in that solution.

Hydrochloric Acid (HCl):

in solution

Properties of Acids Sour Taste (Lemons contain Citric Acid) React with Metals to corrode them (Acid Rain!) Conduct electricity (free ions) pH less than 7 Turns blue litmus paper RED

Examples you need to know:Hydrochloric Acid HClSulfuric Acid H2SO4

Nitric Acid HNO3

Ethanoic / Acetic Acid CH3COOH

Notice all the Hydrogen??

Chemical Formula Name Use

HCl Hydrochloric acid

Digest food in your stomach

HNO3Nitric acid Used to produce

fertilisers

H3PO4Phosphoric acid Removes rust from

metal surfaces

H2SO4Sulfuric acid Used in the liquid in car

batteries

CH3COOH Ethanoic acid (acid acid)

Vinegar

HF Hydrofluoric acid

Breakdown tissue very quickly!

C6H8O7Citric acid Lemons and limes

What makes a Base? It’s all about Hydroxide ions (OH-)

When a base is in solution, it produces Hydroxide ions in that solution.

Sodium Hydroxide:

in solution

Properties of Bases Bitter (Chalky) Taste Feel soapy/slippery Conduct electricity (free ions) pH more than 7 Turns red litmus paper BLUE

Examples you need to know:Sodium Hydroxide NaOHPotassium Hydroxide KOHSodium Bicarbonate NaHCO3

Magnesium Hydroxide Mg(OH)2

Notice all the Hydrogen AND Oxygen??

Chemical Formula Name Use

NaOH Sodium hydroxide Caustic soda(drain cleaner; soap

production)

KOH Potassium hydroxide

Used to make liquid soap

NaHCO3Sodium hydrogen

carbonate OR Sodium

bicarbonate

Bicarb soda

Mg(OH)2Magnesium hydroxide

Milk of magnesia –Antacid

(relieves constipationand heartburn)

Combining Acids and Bases When an Acid and Base are combined, the Hydrogen Ions and

Hydroxide Ions combine chemically to form Water. This is called Neutralisation.

The other components of the acids and bases form a Salt (Ionic Compound)

Acid + Base Water + Salt

Can you write the chemical equation for the following:

1. Hydrochloric Acid combined with Sodium Hydroxide

2. Sulfuric Acid combined with Potassium Hydroxide

Neutralisation EquationsAcid + Base Water + Salt

Hydrochloric Acid + Sodium Hydroxide Water + Sodium Chloride

HCl + NaOH H2O + NaCl

Now balance:

HCl + NaOH H2O + NaCl

(already balanced)

Neutralisation EquationsAcid + Base Water + Salt

Sulfuric Acid+ Potassium Hydroxide Water + Potassium Sulfate

H2SO4 + KOH H2O + K2SO4

Now balance:

H2SO4 + 2KOH 2H2O + K2SO4