Chemical changes Flashcards
What do metals react with oxygen to produce?
Metal oxides.
What happens in an oxidation reaction?
A substance (metal) gains oxygen.
Oxidation reaction word equation
Metal + Oxygen → Metal Oxide
What are oxides often?
The ores that metals need to be extracted from.
What is a reaction that separates a metal from its oxide called?
A reduction reaction.
Reduction of a Metal Oxide using carbon equation
Metal Oxide + Carbon → Pure Metal + Carbon Dioxide
What is reduction?
-The loss of oxygen
-The gaining of electrons
What is oxidation?
-The gaining of oxygen
-The loss of electrons
Give the symbol equation for the oxidation of magnesium oxide.
2Mg + O₂ → 2MgO
2Mg + O₂ → 2MgO
What happens to magnesium in this reaction?
It is oxidised to make magnesium oxide.
Give the symbol equation for the reduction of copper oxide.
2CuO + C → 2Cu + CO₂
How are unreactive metals such as gold found in the Earth?
As a pure metal
How are most metals found?
As compounds that require chemical reactions to extract the metal.
How can metals less reactive than carbon be extracted from their oxides?
Reduction with carbon.
Why is reduction with carbon a redox reaction?
-The ore is reduced as oxygen is removed from it
-Carbon gains oxygen so is oxidised
Why do metals more reactive than carbon have to be extracted using electrolysis?
Carbon is less reactive than the metals so cannot displace them from their oxides.
How is iron oxide reduced?
In a blast furnace to make iron.
What are ionic equations?
Equations showing only the substances being oxidised or reduced (losing or gaining electrons).
What must ionic equations include?
State symbols!
What do we call ions that don’t change in an equation?
Spectator ions.
What is reduction with carbon a special kind of?
Displacement reaction.
What are species (chemistry)
A set of molecular entities which are chemically identical
(basically if an atom is identical to another atom, they are defined as being the same chemical species).
What is the reactivity of a metal related to?
Its tendency to lose electrons and form positive ions.
What does the reactivity series show?
Metals, arranged in order of their reactivity (with other substances).