Copy and complete table 3 . Element Density / g cm - 3 Length of cubic crystal edge/ pm Radius of atom from X - ray diffraction data/ pm Crystal type iron 125 BCC sodium 0 . 968 429 platinum 21 . 09 FCC

The density of the unit cell, d = zM a 3 N A . Where, z = No . of atoms ; M = atomic mass ; a = edge length ; N A = Avogadro ' s number . The relationship between the edge length and the radius of SC ; BCC ; FCC are given as, SC ⇒ a = 2 r . BCC ⇒ 3 a = 4 r . FCC ⇒ 2 a = 4 r . For iron, The edge length, 3 a = 4 r ⇒ a = 4 r 3 = 4 × 125 1 . 732 = 500 1 . 732 = 288 . 68 pm . The density, d = zM a 3 N A = 2 × 56 g mol - 1 2 . 8868 × 10 - 8 cm 3 × 6 . 022 × 10 23 mol - 1 . d = 112 g mol - 1 2 . 405 × 10 - 23 cm 3 × 6 . 022 × 10 23 mol - 1 . d = 112 g 14 . 48 cm 3 = 7 . 73 g cm - 3 . For sodium, d = zM a 3 N A ⇒ z = d × a 3 × N A M = 0 . 968 g cm - 3 × 4 . 29 × 10 - 8 cm 3 × 6 . 022 × 10 23 mol - 1 23 g mol - 1 . z = 0 . 968 × 7 . 89 × 10 - 23 × 6 . 022 × 10 23 23 = 45 . 993 23 = 2 . The number of atom is two. Therefore, the crystal structure is body-centred cubic unit cell. The radius will be, 3 a = 4 r ⇒ r = 3 a 4 = 1 . 732 × 429 4 = 185 . 757 pm . For platinum, d = zM a 3 N A ⇒ a 3 = z × M d × N A . a 3 = 4 × 195 g mol - 1 21 . 09 g cm - 3 × 6 . 022 × 10 23 mol - 1 a 3 = 780 × 10 - 23 cm 3 127 = 6 . 14 × 10 - 23 cm 3 . a 3 = 61 . 4 × 10 - 24 cm 3 ⇒ a = 61 . 4 × 10 - 24 cm 3 3 a = 3 . 94 × 10 - 8 cm = 394 pm . The radius for face-centred cubic unit cell, 2 a = 4 r ⇒ r = 2 a 4 = 1 . 414 × 394 4 = 139 . 27 pm . The completed table 3 is given as, Element Density/ g cm - 3 Length of cubic crystal edge/ pm Radius of atom from X - ray diffraction data/ pm Crystal type iron 7 . 73 288 . 68 125 BCC sodium 0 . 968 429 185 . 75 BCC platinum 21 . 09 394 139 . 27 FCC

E M B I B E

Oxford IB Diploma Programme Chemistry Course Companion>Chapter 22 - Materials>Questions

Sergey Bylikin, Gary Horner and, Brian Murphy Solutions for Chapter: Materials, Exercise 14: Questions

Author:Sergey Bylikin, Gary Horner & Brian Murphy

Sergey Bylikin Chemistry Solutions for Exercise - Sergey Bylikin, Gary Horner and, Brian Murphy Solutions for Chapter: Materials, Exercise 14: Questions

Attempt the practice questions on Chapter 22: Materials, Exercise 14: Questions with hints and solutions to strengthen your understanding. Oxford IB Diploma Programme Chemistry Course Companion solutions are prepared by Experienced Embibe Experts.

Questions from Sergey Bylikin, Gary Horner and, Brian Murphy Solutions for Chapter: Materials, Exercise 14: Questions with Hints & Solutions

EASY

Diploma

IMPORTANT

Oxford IB Diploma Programme Chemistry Course Companion>Chapter 22 - Materials>Questions>Q 4

Draw structures representing a face centred cubic and body centred cubic unit cell.

EASY

Diploma

IMPORTANT

Oxford IB Diploma Programme Chemistry Course Companion>Chapter 22 - Materials>Questions>Q 6

Sketch a graph of resistance versus temperature for a conductor and a superconductor.

MEDIUM

Diploma

IMPORTANT

Oxford IB Diploma Programme Chemistry Course Companion>Chapter 22 - Materials>Questions>Q 8

Copy and complete table $3$ .

Element	Density / $g {cm}^{- 3}$	Length of cubic crystal edge/ $pm$	Radius of atom from $X -$ ray diffraction data/ $pm$	Crystal type
iron			$125$	$BCC$
sodium	$0.968$	$429$
platinum	$21.09$			$FCC$

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