O-LevelChemistryBonding & Structure5070/22 · May/June 2019 · Q37 Marks

Titanium, Ti, is a metallic element.

(a)Suggest one physical property of titanium.[1]
(b)(i)Titanium(IV) chloride, TiCl4, is a colourless liquid that has a low boiling point. (i) Suggest the structure and bonding in TiCl4.[1]
(b)(ii)Titanium(IV) chloride reacts with water to form hydrochloric acid and a precipitate of titanium(IV) oxide. Construct the equation, including state symbols, for this reaction.[2]
(c)Titanium is made by reducing TiCl4 using magnesium. TiCl4 + 2Mg → 2MgCl2 + Ti Calculate the mass of titanium made from 1000 g of TiCl4. The reaction has a 90% percentage yield. Give the answer to two significant figures. [The relative atomic mass of titanium, Ti, is 48.] mass of Ti ..................................................... g[3]

Mark scheme

Marking points from the official mark scheme (May/June 2019). The mark or mark type is shown in brackets.

[1] 3(a) high melting point/ high boiling point/ high density / (good) conductor of electricity / (good) conductor of heat / malleable / ductile / hard / strong / sonorous
[1] 3(b)(i) simple covalent molecule / simple covalent molecular
[2] 3(b)(ii) TiCl 4(l) + 2H2O(l) → TiO2(s) + 4HCl(aq) balanced equation (1) state symbols – dependent on correct formulae (1)
[3] 3(c) Process 1: mol TiCl4 = 1000/190 OR 5.263 (1) Process 2: mass Ti = 1000/190 × 48 OR 252.63 (1) Process 3: % = 1000/190 × 48 × 0.9 OR 227.36 / 230g OR Process 1: mol TiCl4 = 1000/90 OR 5.263 (1) Process 2: % = 90/100 × 5.263 OR 4.736 (1) Process 3: mass = 4.736 × 48 OR_227.36/230 g

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