Topic 4- Chemical changes Flashcards
What is oxidation/reduction?
oxidation- when a substance gains oxygen
reduction- when a substance loses oxygen
What is the reactivity series of metals? What are the trends in reactivities of metals in reactions with acids/water?
The series show the metals in order of reactivity
Metals above H2 in reactivity series react with acid to produce H2.The more reactive the metal is the quicker and more violent reaction with acid occurs
metals below H2 don’t react with acids
Not all metals above H2 react with water - mostly group 1 and 2 metals and aluminium
What is a displacement reaction?
A reaction where a more reactive metal displaces a less reactive metal from a compound
How are unreactive metals found in Earth?
In their natural state
How can metals less reactive than carbon be extracted?
reduction with carbon. Carbon displaces the metal in a metal oxide- gets oxidised to carbon oxides. Metal from the metal oxide gets reduced to the pure metal
How are metals more reactive than carbon extracted?
by electrolysis
How are oxidation and reduction defined in terms of electron transfer?
oxidation - loss of electrons
reduction - gain of electrons
What is the general equation for a reaction between metals and acids? What type of reaction is this?
Metal + Acid = salt + hydrogen
Redox reaction, also a displacement reaction
Which metals in the reactivity series will react with acid?
those above hydrogen
What is the general equation for a neutralisation reaction?
Base + Acid = salt + water
What is the general equation for the reaction between metal carbonate and acid
metal carbonate + acid = salt + water + carbon dioxide
what is the general equation for the reaction between metal oxides and acids?
metal oxide + acid = salt + water
What is a redox reaction?
A reaction where both oxidation and reductio occurs
Explain in terms of gain or loss of electrons which species has been oxidised and which species has been reduced when magnesium reacts with hydrochloric acid
Magnesium has lost electrons and thus has been oxidised (Mg to Mg2+)
The hydrogen in HCl has gained electrons and thus has been reduced (H to H2)
How is soluble salt formed?
React the excess acid with some insoluble chemical
filter off the leftovers
crystallise the product