Bonding, Structure & the Properties of Matter

Question 1

Describe how metals conduct electricity. [3 marks]

Answer 1

delocalised electrons
(the electrons) carry (electrical) charge
(the electrons move) through the metal / aluminium / structure

Question 2

Explain why diamond has a very high melting point. [3 marks]

Got 2/3 on March 29th March

Answer 2

• (covalent) bonds are strong
  * (and many covalent) bonds must be broken
• (so) a lot of energy is required

Question 3

Molecules such as C₇₀ can be used in medicine to move drugs around the body.
Suggest one reason why the C₇₀ molecule is suitable for this use. [1 mark]

Answer 3

any one from:
* (C₇₀ is) hollow
* (C₇₀ is) unreactive
* (C₇₀ is) not toxic
* (C₇₀ has) a large surface area to volume ratio

allow (C₇₀) acts as a cage
allow (C₇₀) traps the drug

Question 4

Calculate the number of C₇₀ molecules that can be made from one mole of
carbon atoms.
The Avogadro constant = 6.02 × 10²³ per mole [3 marks]

Answer 4

(moles of C₇₀ molecules =
1/70 =) 0.01̇ 42857̇
(molecules =) 0.01̇42857̇ × 6.02 × 10²³ = 8.6 × 10²¹

Question 5

Why, when crystalising zinc oxide, is excess zinc oxide used rather than excess hydrochloric acid? [1 mark]

Answer 5

(excess) zinc oxide can be filtered off
allow separation / removal of (excess) zinc oxide is easier

Question 6

Describe how the student should obtain crystals of zinc chloride from a solution of zinc chloride. [2 marks]

Answer 6

heat (the solution) until crystallisation point is reached / until crystals start to form
leave the solution (to cool / crystallise)

Question 7

Zinc and copper can be used with another substance to produce electricity.
Complete Figure 7 to show how zinc, copper and another substance can be used to light a lamp.
Label:
* zinc
* copper
* the other substance used.
The circle with a cross inside represents the lamp. [3 marks]

Figure 7: https://cdn.discordapp.com/attachments/1062056354874937405/1224472744012419072/image.png?ex=661d9e1b&is=660b291b&hm=f629a7037cf733bd84e45dcc09dc506b16facea9db72ed2132e5af6d3796d5a8&

Got 2/3 on March 29th.

Answer 7

(a diagram showing) solution in a container

zinc electrode
and
copper electrode
both inserted into solution

complete circuit that would function as an electrochemical cell including a labelled
electrolyte / a named molten electrolyte (may be in solution)

do not accept cell / battery in external circuit
do not accept a wire between the electrodes

Full mark diagram:
https://cdn.discordapp.com/attachments/1062056354874937405/1224473202525212713/image.png?ex=661d9e89&is=660b2989&hm=46e4be34f86431c85e9f87066d02ce25836751436e28ffee4f1525dd047e883f&