Chemistry Topic 4 Flashcards
What is a metal oxide?
A chemical compound that contains a metal chemically combined with oxygen
What is oxidation?
A reaction in which oxygen is added to an element or compound
What is reduction?
Oxygen is removed from an element or compound
OILRIG:
Oxidation is loss, reduction is gain (of electrons)
What is a REDOX reaction?
A chemical reaction which involves both reduction and oxidation
Reactivity series:
- metals at the top are more reactive as they loose electrons easily
- carbon and hydrogen are not metals but included as they are used in extracting metals
Displacement reaction:
A more reactive element will displace a less reactive element from its compounds - a metal will displace another metal below in the reactivity series
Do metals react with water?
Metals above hydrogen in the reactivity series react with water
Equation for metals reacting with water:
Metal + water –> metal hydroxide + hydrogen
Do metals react with acids?
Most metals react with dilute acids like HCL. Only metals above hydrogen in the reactivity series react to acid
Equation for metals reacting with acids:
Metal + acid —> metal salt + hydrogen
What is an ore?
A naturally occurring solid material from which a metal or valuable mineral can be profitably extracted
How can metals be extracted by their ores?
👉 Reduction with carbon: can only be done if the metal is less reactive than carbon
👉 Electrolysis: can be done with all metals, but require a large amount of energy and money
What’s hematite and what’s a bauxite?
Hematite- Iron ore
Bauxite- aluminium ore
Why do Un reactive metals not have to be extracted?
- typically found as the uncombined element- they don’t easily react to other substances due to their chemical stability. E.g. Gold can be mined directly from the earths crust
What does a neutralisation reaction produce and what is its equation?
- produces water
- acid + base —> salt + water
Equation for reduction by carbon:
Metal + oxide —> metal + carbon dioxide
What is an alkali metal?
An element of group 1 on the periodic table - a base that can dissolve in water
What is a salt?
A compound formed when the hydrogen ion in an acid is replaced by a metal ion
How can a soluble salt be made?
👉 - can be made through the reaction of an acid with an insolvable base
👉 - an excess of the insoluble base is added to ensure all the acid has reached
👉 - the excess is removed through filtration
👉 - all that’s left in the solution is salt and water
What makes a solution acidic?
The presence of hydrogen ions (H+)
What happens when acids are added to water?
They form positively charged hydrogen ions (H+)
What makes a solution alkaline?
The presence of OH- ions
What happens when alkalis are added to water?
They form negative hydroxide ions (OH-)
