Topic 4: Chemical Changes Flashcards
(23 cards)
Strong acids
Acids that ionise completely in water i.e. all acid particles dissociate to release H+ ions
Weak acids
Acids that do not fully ionise in water i.e. only a small proportion of acid particles dissociate to release H+ ions
pH (2)
A measure of the concentration of H+ ions in the solution
Increases by a factor of 10 as pH decreases by 1
Concentration of acid
How much acid in a certain volume of liquid
Acid strength
What proportion of the acid molecules ionise in water
Acid + Metal Oxides
Salt + Water
Acid + Metal Hydroxide
Salt + Water
Acid + Metal Carbonate
Salt + Water + Carbon Dioxide
SOLUBLE SALTS PRACTICAL
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Reactivity Series
Potassium Sodium Lithium Calcium Magnesium Aluminium Carbon Zinc Iron Hydrogen Copper Silver Gold Platinum
Acid + Metal
Salt + Hydrogen
Metal + Water
Metal Hydroxide + Hydrogen
Formation of a metal ore
Metal + Oxygen –> Metal Oxide
Extraction of metal with carbon
Metal Oxide + Carbon –> Metal + Carbon Dioxide
Oxidation
Gain of oxygen
Loss of electrons
Reduction
Loss of oxygen
Gain of electrons
Cathode
The negative electrode which the positive ions will move towards
Anode
The positive electrode which the negative ions will move towards
At the cathode…
Positive metal or hydrogen ions are reduced to their element
At the anode…
Negative non-metal ions are oxidised to their element
When will hydrogen form at the cathode?
When the metal ion forms an metal element that is more reactive than hydrogen
What will form at the anode if halides (chloride, bromide and iodide) aren’t present?
Hydroxide ions will be attracted to the anode and oxygen and water will form
ELECTROLYSIS PRACTICAL
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