DP Chemistry (last assessment 2024)

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Question 18M.3.sl.TZ2.1a.iii

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Date May 2018 Marks available [Maximum mark: 1] Reference code 18M.3.sl.TZ2.1a.iii
Level sl Paper 3 Time zone TZ2
Command term Identify Question number a.iii Adapted from N/A
a.iii.
[Maximum mark: 1]
18M.3.sl.TZ2.1a.iii

The table summarizes some properties of graphite and graphene.

M18/4/CHEMI/SP3/ENG/TZ2/01

(a.iii)

Identify a value from the table which can be used to support the information about graphene given below.

M18/4/CHEMI/SP3/ENG/TZ2/01.a.iii_01

Electrons in a solid are restricted to certain ranges, or bands, of energy (vertical axis). In an insulator or semiconductor, an electron bound to an atom can break free only if it gets enough energy from heat or a passing photon to jump the “band gap”, but in graphene the gap is infinitely small.

                                                           M18/4/CHEMI/SP3/ENG/TZ2/01.a.iii_02

[1]

Markscheme

«graphene has a high electron mobility of» 15 000–200 000 «cm2 V–1 s–1»

 

A specific value or range of values must be given.

Accept any value in the 15 000–200 000 «cm2 V–1 s–1» range.

[1 mark]

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