Chemical Changes Flashcards
Acids ionise in water to produce….
hydrogen ions H+
Alkalis ionise in water to produce….
Hydroxide ions, OH-
What is a base?
A substance that neutralises an acid
Suggest the pH of hydrochloric acid
1-4
Suggest the pH of sodium hydroxide
10-14
Acid + Metal =
Salt + Hydrogen (MASH)
Acid + Metal Oxide =
Salt + Water
Acid + Alkali =
Salt + Water
Acid + Metal Carbonate =
Salt + carbon dioxide + water
Magnesium + Hydrochloric acid =
Magnesium Chloride + Hydrogen
Sodium Hydroxide + Nitric acid =
Sodium nitrate + water
Copper Oxide + sulphuric acid =
Copper sulphate + water
Calcium Carbonate + Hydrochloric acid =
Calcium chloride + Carbon Dioxide + water
List the steps to make copper sulphate crystals
Warm sulphuric acid Add copper oxide until it is in excess Filter the excess copper oxide Evaporate the water in an evaporating dish
How can a precipitate, such as lead iodide, be removed from a solution?
Filter it
What is the positive electrode in electrolysis called?
Anode (PANic)
What is the negative electrode in electrolysis called?
Cathode (PANiC)
In the electrolysis of lead iodide, why does the lead iodide have to be melted?
so the ions can move and carry the charge
In the electrolysis of lead iodide, which electrode do the lead ions go to?
Cathode
Explain why copper ions go to the cathode
The cathode is negative Copper ions are positive Opposite charges attract
Explain why chloride ions go to the anode
The anode is positive Chloride ions are negative Opposite charges attract
Finish the following equation Pb2+ + __ e- –> Pb
Pb2+ + 2e- –> Pb
How does a copper ion, Cu2+, become a copper ion?
By gaining two electrons
What is the aluminium ore called?
Bauxite
Why is molten cryolite added to the aluminium oxide?
To reduce the melting point so less energy is required
Name the three products of the electrolysis of brine
Sodium hydroxide Hydrogen Chlorine (CatHy’s AnCls)
The loss of electrons is called
Oxidation (OILRIG)
The gain of electrons is called
Reduction (OILRIG)
Why is hydrogen produced instead of sodium in the electrolysis of brine?
Sodium is more reactive than hydrogen
Why can carbon be used to extract copper from copper oxide?
Carbon is more reactive
Why can’t aluminium be extracted from aluminium oxide by reducing it with carbon?
Aluminium is more reactive
In electrolysis of aluminium, why do the electrodes need to be replaced?
-The electrodes are made of carbon -They react with the oxygen -To form carbon dioxide
