Flashcards in Topic 3 - Chemical Changes Deck (23):
Reacts with acid to form a salt + water
Red - acidic
Purple - neutral
Blue - Alkali
Red - acidic
Yellow - neutral + alkali
Colourless - acidic or neutral
Pink - alkali
When in water they disassociate.
Don’t fully disassociate. In a reversible reaction at equilibrium.
Acid strength PH
Tells the proportion of disassociation.
Measures how much acid in one dm^3
By increasing the concentration by a factor of 10.
The PH rises by 1.
Make insoluble salt
2 soluble salts picked and reacted
Collect insoluble salt.
Dissolve 2 soluble salts. Add them together. Allow precipitate to form. FILTER. Swill out contents to collect all precipitate. Rinse all insoluble salt with water to remove soluble salts. Collect and dry.
Make a soluble salt
Acid + insoluble base (BASHO)
Acid + alkali (soluble, BASHO)
Soluble salt by acid and insoluble base
Choose the correct reactants by the ions you need.
1. Heat acid to increase rate of reaction
2. Add insoluble base in excess (ensuring there’s no leftover acid in product)
3. Filter excess solid to acquire a solution (salt + water)
4. Evaporate off water and allow it to crystallise.
Soluble salt by acid + alkali (soluble base)
Titration - as there’s no visible sign that the reaction has finished.
Using a burette slowly add alkali to the acid until the chosen indicator changes colour.
Collect solution and evaporate.
Positive ions move to and are reduced (gain)
Negative ions are attracted and oxidised (loss)
Electrodes must be
Inert (graphite or platinum)
Cathode in aqueous
If the metal is MORE reactive than hydrogen, HYDROGEN GAS IS FORMED
Anode in aqueous
If HALIDE PRESENT, HALIDE GAS forms
If none OXYGEN GAS is formed
Electrolysis of copper sulfate
Produces oxygen, copper is less reactive so copper forms.
Cu 2+ + 2e- -> Cu
4OH- -> O2 + 4H2O + 4 e-