C4 Flashcards
what happened to acids in water
Acids are substances that form hydrogen (H+) ions when they dissolve in water (aqueous solutions).
what happens to alkalis in water
Alkalis are substances that form hydroxide (OH-) ions when they dissolve in water (aqueous solutions).
An alkali is a type of base.
what is oxidisation
An oxidation reaction involves gaining oxygen.
Oxidation reactions can also involve losing electrons.
E.g. when metals react with oxygen, metal oxides are produced:
Calcium + oxygen → calcium oxide
2Ca + O2 → 2CaO
what is reduction
A reduction reaction involves losing oxygen.
Reduction reactions can also involve gaining electrons.
E.g. when metal oxides lose oxygen and return to their atomic form:
Iron oxide + carbon monoxide → iron + carbon dioxide
Fe2O3 + 3CO → 2Fe + 3CO2
what is oil rig
Oxidation
Is
Loss
Reduction
Is
Gain
in terms of electrons
how is the reactivity series set
When reacting with other substances, metal atoms always form positive ions.
The reactivity of a metal is linked to how easy it is for a metal to form its positive ion.
Metals can be arranged in order of their reactivity.
Gold and platinum are examples of highly unreactive metals. These metals are found in the Earth’s crust as pure metals. We call them native metals.
Metals that do react with dilute acids
Metals don’t have to be that reactive to react with dilute acids.
The metals that react with dilute acids but not cold water are magnesium, aluminium, zinc, iron and lead (iron and lead react slowly).
Metals that don’t react with dilute acids
The only metals that aren’t reactive enough are copper, silver, gold and platinum.
why are most metals found as compounds
Most metals are only found as compounds because the metal has reacted with other elements in the past. Because of this, the metal has to be extracted from the ore (rock) where the metal compound is found.
Why is carbon used to extract metals
Reducing a metal with carbon will result in the extraction of the metal if the metal is lower in the reactivity series than carbon.
Carbon is used because it is cheap and abundant.
How is carbon used to extract metals?
In the reduction, the metal oxide loses oxygen to form a pure metal.
Reduction with carbon normally involves heating the metal oxide in the presence of the carbon, which is often used in the form of coal.
Reaction of Metals with Acids
When acids react with metals, hydrogen and a salt are always formed. The first part of the salt’s name comes from the metal involved. The second part of the name comes from the acid.
