How structure influences the properties and uses of substances Flashcards Preview

GCSE Chemistry Unit 2 > How structure influences the properties and uses of substances > Flashcards

Flashcards in How structure influences the properties and uses of substances Deck (18)
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1

Why does pure water not conduct electricity? [1]

- no delocalised / free electrons
- no overall electric charge
- no ions

2

How does the size of a nanoparticle compare with the size of an atom? [1]

nanoparticles are larger

3

Suggest one reason why 1 g of cobalt oxide nanoparticles is a better catalyst than 1 g of cobalt oxide powder. [1]

nanoparticles have a larger surface area

4

Explain why metals can be bent and shaped. [2]

- layers of particles / atoms...
- ...slide over each other

5

Explain how copper conducts electricity. [2]

- it has delocalised electrons...
- ...and therefore can move through the structure

6

Explain why diamond is hard. [2]

- it's a giant structure...
- ...with strong bonds between carbon atoms

7

Explain why thermosetting polymers are better than thermosoftening polymers for saucepan handles. [2]

- thermosetting polymers do not melt (when heated)...
- ...due to cross-links (between chains)

8

Explain how electricity is conducted in a metal. [4]

- giant structure / lattice...
- ...made up of atoms / positive ions
- ...with delocalised electrons...
- ...so electrons can move through the metal

9

Describe how the structure of an alloy is different from the structure of a pure metal. [2]

- an alloy has different types / sizes of atoms...
- ...resulting in distorted layers

10

Why is Nitinol used in dental braces? [1]

it can return to its original shape

11

Suggest one reason why coins are not made of pure copper. [1]

pure copper is too soft

12

Aluminium is manufactured by the electrolysis of a molten mixture of cryolite and ________. [1]

aluminium oxide

13

How can the same reaction produce two different products? [1]

different...
- conditions
- catalyst
- pressure
- temperature

14

Give two reasons why instrumental methods of analysis are used to detect impurities in metals. [1]

- accurate
- sensitive
- rapid
- small sample

15

Suggest why carbon nanotubes are used as lubricants. [2]

- nanotubes can slide (over each other)...
- ...because there are no (covalent) bonds between the nanotubes

16

Explain why graphite can conduct electricity. [2]

- graphite has delocalised electrons...
- ...so that electrons can move through the graphite
- ...so that electrons can carry charge through the graphite

17

Describe, as fully as you can, the structure and bonding in diamond. [4]

- giant structure / lattice
- strong bonds (between carbon / atom)
- covalent (bonds)
- each carbon / atom forms 4 bonds

18

Describe the structure and bonding in a thermosoftening polymer and explain why
thermosoftening polymers melt when heated. [4]

- chains or large molecules...
- ...with intermolecular forces...
- ...that are weak...
- ...and are easily broken (when heated)