Chemical Changes Flashcards
What is electrolysis?
The process of breaking down a compound using electricity.
Why must the compound be molten?
So the ions can move around freely.
Why is cryolite used in the extraction of aluminium?
Cryolite lowers the melting point which reduces energy costs.
What would form at the anode in the electrolysis of sodium chloride?
Chlorine
What would form at the cathode in the electrolysis of sodium chloride?
Sodium
Why would sodium form at the cathode when the compound is aqueous?
Sodium is more reactive than hydrogen.
What is an anode?
The positive electrode which attracts anions that are negative.
What is a cathode?
The negative electrode which attracts cations that are positive.
How much do strong acids ionise in solutions?
Fully
How much do weak acids ionise in solutions?
Partially
Describe acid particles within concentrated acids?
They have a bigger number per volume of water.
Describe acid particles within dilute acids?
They have a smaller number per volume of water.
What is the proper name for table salt?
Sodium chloride
What are salts made out of?
Ions with an opposite charge.
How are salts made?
By an acid reacting with a base.
What are the three common endings on the end of the salt names?
Sulfate, chloride and nitrate
Na0H + H2SO4 =
Na2SO4 + H2O
LiOH + HCl =
LiCl + H2O
KOH + H2SO4 =
K2SO4 + H2O
Ca(OH)2 + HNO3 =
Ca(NO3)2 + H2O
Copper carbonate + nitric acid =
Copper nitrate + carbon dioxide + water
Sulfuric acid + calcium carbonate =
Calcium sulfate + carbon dioxide + water
Zinc oxide + sulphuric acid =
Zinc sulfate + water
Nitric acid + copper oxide =
Copper nitrate + water
Hydrochloric acid + calcium hydroxide =
Calcium chloride + water
Magnesium hydroxide + hydrochloric acid =
Magnesium chloride + water
What is an acid?
A chemical which tastes sharp, is corrosive and releases hydrogen ions in water.
What is an alkali?
A chemical which is corrosive, is used to make soap and releases hydroxide ions in water.
What is a base?
A chemical which neutralises acid but does not necessarily dissolve in water.
What is an indicator?
A substance which has a different colour at different pH values.
What does neutral mean?
Neither acidic or alkaline (pH7)
When does neutralisation occur?
When an acid is neutralised by an alkali.
What is the pH for acids?
Between 0 and 7. The more acidic the liquid the lower the pH.
What is the pH for alkalis?
Between 7 and 14. The more alkaline the liquid the higher the pH.
If an alkali of pH 10 was added to an equal amount of acid of pH what would the result be?
The solution would be neutral.
What metals can be extracted by electrolysis?
Potassium, sodium, calcium, magnesium and aluminium.
What is the term for something gaining oxygen?
It has being oxidised, this is called oxidisation.
What is the term for something losing oxygen?
It is being reduced, this is called reduction.
How does carbon become carbon dioxide?
When it takes oxygen from the metal oxide?