Acids & Bases Flashcards
Definition of Acids
A substance that produces Hydrogen ion (H+) in aqueous solutions
Types of Acids
Dilute hydrochloric acid HCL
dilute sulfuric acid H2SO4
Dilute Nitric acid HNO3
Dilute ethanoic acid CH3COOH
Characteristic properties of acids
- acids has a pH less than 7 ( in aqueous state/solution)
- Turns damp blue litmus paper red
- Changes colour of Universal indicator from green to red, orange & yellow
- Conducts electricity in aqueous state = delocalised mobile oppositely changed ions in the solution
- Are corrosive
- Sour taste
What pH has the highest concentration of Hydrogen ions
1
What pH level has the highest concentration of Hydroxide ions
14
Definition of alkali & bases
A substance that produces hydroxide ion (OH-) in aqueous solutions
Types of bases
All metal oxides
Eg: MgO,CaO,CuO,Fe2O3
Types of Alkali
Generally group 1 hydroxides.
Eg: NaOH, KOH, LiOH
Characteristic properties of alkali & bases
- Alkali has a pH of more than 7 (in aqueous state/solution)
- Turns damp red litmus paper blue
- Changes colour of universal Indicator from green to blue/violet
- Conducts electricity in aqueous state = delocalised mobile oppositely charged ions in the solution.
- Are corrosive
- Bitter taste
Dilute acid + metal ->
Salt + hydrogen gas
Observation for [dilute acid + metal -> salt + hydrogen gas]
-Effervescence observed. Gas produced is hydrogen gas
-metal reacts vigorously with the dilute acid and as the reaction proceed, the size of the metal decreases
Test for [dilute acid + metal -> salt + hydrogen gas]
Test H2 gas produced using a lighted splint; flame will extinguish with a ‘POP’ sound
Dilute acid + base/alkali ->
Salt + water
Neutralisation
Represented as ionic equation: H+ + OH- ->H2O
Dilute acid + metal carbonate ->
Salt + water + carbon dioxide
Observations for [dilute acid + metal carbonate -> salt + water + carbon dioxide]
Vigorous reaction between dilute acid and metal carbonate
Effervescence observed. Gas produced is CO2
Size of metal carbonate decreases a reaction proceeds
Test for [dilute acid + metal carbonate -> salt + water + carbon dioxide]
Bubble the gas produced through limewater, white precipitate formed in limewater
Alkali/base + ammonium salt ->
Salt + water + ammonia gas
Observation for [Alkali/base +ammonium salt -> salt + water + ammonia gas]
Upon gentle warming of the reaction mixture, a Colourless pungent gas evolved.
Test for [Alkali/base +ammonium salt -> salt + water + ammonia gas]
Colourless pungent gas turns damp red litmus paper blue; gas produced is ammonia
Fertiliser & lime reacts to form…
Ammonia gas, which has a high composition of nitrogen
If soil is not treated, it will remain acidic
Basic oxides
Any metal oxide
Reacts with acid to form salt and water
Usually solid, ionic compound
Acidic oxide
Any non-metal oxides
Eg. Sulfur dioxide, carbon dioxide
Reacts with bases to form salt & water
Usually gasses/liquids, a simple covalent compound
Amphoteric oxide
“Z.A.P” oxides
Zinc oxide, Aluminium oxide, lead oxide
Will react with both acids & bases
Usually solid, ionic compound
Neutral oxide
“NO COld WATER”
nitrogen monoxide, carbon monoxide & water
Will not react to acids or bases.
Usually gases/liquids, a simple covalent compound
what is used to reduce acidity of soil?
calcium hydroxide
what causes acid rain?
sulfur dioxide
nitrogen dioxide
what is formed from the incomplete combustion of methane
carbon monoxide
formula of potassium oxide
K2O
formula of aluminum oxide
Al2O3
2 chemical properties of alkali
alkali reacts with acids to form salt & water
alkali reacts with ammonium salts to form salt, water & ammonia gas
