Acids and Alkalis

• What can you use to see the acidity of a solution

  universal indicator
• The colour scale when using universal indicator

  
• Acid forms from H+ ions in water
• Base is a substance with a pH level higher than 7
• An alkali is a base that dissolves in water to form a solution with a pH greater than 7
• Alkalis form OH- ions in water
• Neutralisation formula (words)

  acid + base ——> salt + water
• Neutralisation formula (symbols)

  H+ + OH- ——> H2O
• A strong acid has lots of H+ ions available
• Acids are red to yellow
• Alkalis are blue to purple
• neutrals are green (7) like water
• the pH of and unknown substance is found to be 8, is the substance acidic or alkaline?

  Alkaline
• What can be used instead of and indicator when testing pH

  A pH probe
• Concentration is the ratio of water to acid
• Acid + Metal Oxide ——> Salt + Water
• Acid + Metal Hydroxide ——> Salt + Water
• Metal Oxide, Metal Hydroxide and Metal Carbonate are all bases that can be reacted with an acid to neutralise it
• Acid + Metal Carbonate ——> Salt + Water + Carbon Dioxide