P1: Chemical Changes Flashcards
The more reactive a metal is…
-The more vigorous its reactions are
-The more easily it loses electrons to form ions
What are the products of reactions of metals with water?
A metal hydroxide and hydrogen.
What is produced when a metal reacts with a dilute acid?
A salt and hydrogen
What are the products of a reaction of metal with oxygen?
A metal oxide.
What type of metal displaces another one in a displacement reaction?
A more reactive metal displaces a less reactive one,
What is oxidation?
The gain of oxygen or loss of electrons
What is reduction?
The loss of oxygen or gaining of electrons.
What is ore?
A rock containing enough quantities of a mineral for extraction to be possible.
What are the problems with extracting aluminium from its ore?
Aluminium has a high melting point, and aluminium oxide is insoluble in water.
What is used instead of water to extract aluminium from aluminium oxide?
Cryolite.
What are the electrodes in electrolysis made out of?
Graphite.
What is the name of the positive electrode?
Anode
What is the name of the negative electrode?
Cathode.
What happens at the electrodes during the electrolysis of aluminium oxide?
-At the cathode, aluminium ions gain electrons and form atoms.
-At the anode, oxide ions lose electrons and form oxygen gas.
What do acids produce in aqueous solution?
H+ ions
What do alkalis produce in aqueous solution?
OH- ions
What is the name of the scale that measures the acidity or alkalinity of a solution?
pH scale.
What is a base?
Any substance that reacts with an acid to form a salt and water only. Metal oxides and metal hydroxides are bases.
What is produced when a base reacts with an acid?
Salt and water.
What is the other term for bases that are soluble in water?
Alkalis.
What is a neutralisation reaction?
A reaction between an acid and a base.
How do you make a salt in general?
React a metal oxide with an acid.
What is produced when an acid reacts with a carbonate?
Salt, water and carbon dioxide.
How do you make salt? Explain simply.
-Add powdered insoluble reactant to acid in beaker one spatula at a time. Continue adding powder until it is in excess.
-Filter the mixture in the beaker to remove the excess solid.
-Heat the solution in an evaporating dish over a water bath. Stop heating when small crystals start to appear around the edge of the evaporating basin.
-Leave the solution at room temp for a day.
Give some examples of strong acids.
Nitric acid, sulfuric acid, Hydrochloric acid.
Give an example of a weak acid.
Ethanoic acid.
The higher the concentration of H+ ions in an acidic solution…
The lower the pH.
What equipment is needed for a titration calculation?
-A pipette and filler
-A burette
-A conical flask
-White tile
What is the purpose of titrations?
-To determine the reacting volumes of solutions of an acid and alkali by titration.
-To determine the concentration of one of the solutions.
What are suitable indicators for titration calculations?
Phenolphthalein or methyl orange.
What colour do phenolphthalein change to?
Pink in alkaline conditions, colourless in neutral.
What is the colour change in methyl orange?
In alkali or basic, it is yellow. In acidic, it is red
What are the reagents in a titration calculation?
-An acid of unknown concentration
-Sodium Hydroxide solution of known concentration
-A suitable indicator
What is an electrolyte?
A substance which, when molten or in solution, will conduct an electric current
Which electrode to H+ ions go to?
The cathode.
Which electrode do OH-ions go to?
The anode.
When is hydrogen produced at the cathode?
If the metal is more reactive than hydrogen.
Which 3 metals are less reactive than hydrogen?
Copper, silver and gold.
When do OH- ions NOT go to their electrode?
If Group 7 ions are present
What is a half equation?
An equation that demonstrates how an atom has lost or gained electrons.
Explain why the pH of an acid depends on the strength of the acid.
The stronger an acid the greater the ionisation, so the lower the pH.
Explain why the pH of an acid depends on the concentration of the acid.
The higher the concentration of an acid the more acid in the same volume of solution
So the higher the concentration of the acid the lower the pH
Are alkaline batteries rechargable?
No.
