Group 2 Flashcards
Give one medical use for magnesium hydroxide.
Indigestion relief/laxative/neutralise acid
(b)
Give an equation to show how magnesium is used as the reducing agent in the extraction of titanium.
Explain, in terms of oxidation states, why magnesium is the reducing agent.
2Mg + TiCl4 -+ 2MgCl2 + Ti
Mg changes oxidation state from 0 to +2 so electrons are lost / Ti changes oxidation state from +4 to 0, so gains electrons
(b)
Explain why the second ionisation energy of calcium is lower than the second ionisation energy of potassium.
In Ca+ (outer) electron(s) is further from nucleus
Or Ca+ loses electron from a higher (energy) orbital
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AQA Chemistry A-Level - Group 2 Metals MS
Or Ca+ loses electron from a 4(s) orbital or 4th energy level or 4th energy shell and K+ loses electron from a 3(p) orbital or 3rd energy level or 3rd energy shell
Strontium metal can be extracted by heating strontium oxide with aluminium metal.
In this reaction, strontium vapour and solid aluminium oxide are formed.
Write an equation for the reaction and state the role of the aluminium in the process.
solid.
Explain why strontium forms a vapour but aluminium oxide is formed as a solid
(e)
Magnesium burns with a bright white light and is used in flares and fireworks.
Use your knowledge of the reactions of Group 2 metals with water to explain why water should not be used to put out a fire in which magnesium metal is burning.
Hydrogen produced
Risk of explosion/highly flammable
Aluminium is extracted by electrolysis OR aluminium extraction uses (large amounts of) electricity
Reaction / process / It / the mixture requires heat
It is endothermic
(Ill)
In terms of collision theory explain why, at a fixed temperature, the rate of this reaction doubles when the concentration of the hydrochloric acid doubles
(ill) M1
Twice / double as many particles / hydrogen ions
Twice / double as many effective / successful collisions (in a given time)
OR
Twice / double as many collisions with either sufficient energy to react
OR with Ez E.
C
Write an ionic equation, with state symbols, to show the reaction of calcium with an excess or water.
Medicines for the treatment of nervous disorders often contain calcium bromide
Silver nitrate, acidified with dilute nitric acid, can be used together with another reagent to test for the presence of bromide ions in a solution of a medicine.
Describe briefly how you would carry out this test and state what you would observe.
(c)
Add silver nitrate, then dilute ammonia (solution) M1
Cream ppt
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