Redox Reactions Flashcards
What do we mean when we say a substance has been oxidised?
When a substance gains oxygen
What does oxidation mean in terms of electrons?
Oxidation also means the loss of electrons
Why are most metals usually oxidised?
They have already reacted with the oxygen in the air
Name a metal that is found as an element and why
Gold because it’s an unreactive metal
What is reduction?
The removal of oxygen from a substance
What does the OIL in “OILRIG” stand for?
Oxidation
Is
Loss of electrons
What does RIG in “OILRIG” stand for?
Reduction
Is
Gain of electrons
What does it mean when oxidation and reduction often occur together?
This just means that one substance has LOST oxygen and one has GAINED oxygen
What happens in terms of electrons when a substance has GAINED oxygen and when a substance has LOST oxygen? (2 points)
- oxygen lost= electrons gained (reduction)
- oxygen gained= electrons lost
(Oxidation)
Is this reaction oxidation or reduction: Na—-> Na +
Oxidation= Na has lost electrons
Zinc oxide + magnesium——> zinc + magnesium oxide
: identify which substance is oxidised and which is reduced and explain why in terms of oxygen and electrons. (2 points)
- magnesium is OXIDISED as it has JOINED with oxygen and LOST electrons
- zinc oxide has been REDUCED as it has LOST oxygen and GAINED electrons
Magnesium + iron oxide —-> magnesium oxide + iron
Describe which substance has been oxidised and which has been reduced and explain in terms of oxygen and electrons (2 points)
- magnesium is oxidised as it has joined with oxygen and has lost electrons
- iron oxide has been reduced as it has lost oxygen and gained electrons
Where are many metals found and how is reduction important for this? (2 points)
- many metals are found as oxides or other compounds in the earths crust
- we have to remove oxygen by reduction to get the metal so that we can use it
What is metal extraction?
When we remove oxygen (by reduction) in order to get the metal we want so that we can use it
What determines how a metal is extracted?
The reactivity of a metal
Describe the extraction of platinum, gold and silver
- platinum, gold and silver can occur native+ do not need to be extracted
native= can be found in their pure form in nature
Describe the extraction of metals LESS reactive than CARBON
- metals less reactive than carbon can be extracted from their ores by REDUCTION using carbon, coke or charcoal
Describe the extraction of metals above carbon in reactivity (more reactive)
- metals more reactive than carbon can be extracted using ELECTROLYSIS
Why can zinc, iron, tin and lead be extracted using carbon?
Because carbon can remove the oxygen from them as it is more reactive than the metal
What is a redox reaction?
When reduction and oxidation happen at the same time
