Topic 4; Chemical Changes Flashcards
What is oxidation and reduction?
Oxidation- when substance gains oxygen
Reduction- when substance loses oxygen
What are the trends in reactivities of metals in reactions with acids/water?
Acid: metals above H in series react to produce H. Metals below H don’t react with acid
Water: mostly group 1 + 2 metals react.
What is a displacement reaction?
More reactive metal displaces less reactive metal from a compound
How can metals less reactive than carbon be extracted?
Reduction with carbon. Displaces metal in a metal oxide
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?
Metal + acid -> salt + hydrogen
Redox reaction
Which metals in reactivity series 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 + CO2
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 reduction occurs
How is a soluble salt formed?
React acid with some insoluble chemical
Filter off leftover
Crystallise product
What is the difference between a strong and weak acid?
Strong- completely ionised in aqueous solution
Weak- partially ionised in aqueous solution
What happens to pH as concentration of H increases?
pH decreases
