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Question 1

State one observation when magnesium reacts with steam. Give an equation, including state symbols, for this reaction.(2)

Answer 1

1. Bright light
2. Mg (s) + H2O(l) -> MgO+ H2

Question 2

Describe binding in magnesium

Answer 2

Attraction between lattice of Mg2+ ions
And delocalised electrons

Question 3

Explain in terms of structure and bonding why magnesium chloride has a high melting point

Answer 3

MgCl2 is a giant ionic lattice
There is strong electrostatic forces of attraction
Between Mg2+ and Cl- ions

Question 4

Give one medical use of magnesium hydroxide

Answer 4

Indigestion relief
Or laxative
Or neutralise excess stomach acid

Question 5

Give one medical use for Barium sulfate

Answer 5

Produce an x-ray image of the digestive system

Question 6

Explain why the melting point of magnesium is higher than the melting point of sodium.(2)

Answer 6

1. Mg 2+ has a greater charge density than Na+
2. Stronger attraction to delocalised sea of electrons
   Or 2. Stronger metallic bonding

Question 7

Give an equation to show how magnesium is used as the reducing agent in the extraction if titanium
Explain in terms of oxidation states why magnesium is the reducing agent

Answer 7

Equation: 2Mg + TiCl4 → 2MgCl2 + Ti
Explanation: Either Mg changes oxidation state from 0 to +2 so electrons are lost
Or Ti changes oxidation state from +4 to 0 so gains electrons

Question 8

State what is observed when dilute aqueous sodium hydroxide is added to separate MgCl2 and BaCl2 (2)

Answer 8

1. Observation with MgCl2
   White precipitate is formed
2. Observation with BaCl2
   No visible change