Topic 4- Chemical changes Flashcards
What does a PH scale show?
It is a measure of how acidic or alkaline a solution is. The lower the more acidic. An indicator (dye) is used to measure this, it changes colour.
What is the reactivity series?
It lists metals in order of their reactivity with other substances (eg water or acids) , the easier the react the high up they are.
List the reactivity series
Please Potassium Stop Sodium Calling Calcium Me Magnesium A Aluminium Careless Carbon Zebra Zinc Instead Iron Try Tin Learning Lead How Hydrogen Copper Copper Saves Silver Gold Gold Please Platinum
What are metal ores?
Metal ores are naturally occurring rocks that’s contain metal or metal compounds to make it worthwhile extracting
What is oxidation and reduction?
Oxidation is the gain of oxygen.
Reduction is the loss of oxygen
What is oxidation and reduction in terms of electrons?
Oxidation means the loss of electrons.
Reduction means gaining electrons
OIL RIG= oxidation is loss, reduction is gain
What is a redox reaction ?
When REDuction and OXidation happen at the same time.
Displacement reactions are redox reactions because one of them loses electrons and is oxidised and the other gains electrons and is reduced
What are spectator ions?
ions in an equation that do not change
What are the 2 ways metals can be extracted?
Metals in the reactivity series that are below carbon are extracted by reduction using carbon, this is because carbon can only take away oxygen from anything that is less reactive than carbon itself.
Anything more reactive than carbon is extracted using electrolysis which is expensive.
How does electrolysis happen?
An electric current is passed through and electrolyte (a molten or dissolved compound ). the Ions move towards the electrode and react.
The positive ions will move towards the cathode ( the negative electrode ) and gain electrons (reduced)
and the negative ions will move towards the anode (positive electrode) and lose electrons (oxidised)
