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Chemistry (My Flashcards) > Topic 1 - Types of Substance > Flashcards

Topic 1 - Types of Substance Flashcards

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1
Q

Which is smaller, an atom or a molecule?

A

An atom.

Simple molecules consist of atoms joined by strong covalent bonds within the molecule.

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2
Q

Why do ionic compounds have high melting points?

A

Strong electrostatic attraction between the positive and negative ions requires a lot of energy to overcome.

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3
Q

When do ionic compounds conduct electricity? Why?

A

When molten or aqueous (dissolved in water) because the ions are charged and free to move. When solid, the ions are fixed in an ionic lattice so can’t move.

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4
Q

Why do simple molecular compounds have low melting and boiling points?

A

They have weak intermolecular forces (forces between molecules) which only require a little energy to overcome.

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5
Q

Do simple molecular compounds conduct electricity? Why / why not?

A

No because there are no charged particles.

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6
Q

Do giant covalent structures have a high melting point? Explain your answer.

A

Yes because they have lots of strong covalent bonds which require a lot of energy to break

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7
Q

How do metals conduct electricity and heat?

A

The positive ions are fixed in a sea of delocalised electrons. These electrons are free to move and carry charge / energy.

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8
Q

True or false? ‘Metals are insoluble in water’

A

TRUE

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9
Q

Name two giant covalent structures formed from carbon atoms

A

Graphite

Diamond

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10
Q

Describe the structure and properties relating to graphite

A
  • Each carbon atom bonded to 3 other carbon atoms.
  • Layers of hexagonal rings of carbon atoms.
  • Weak intermolecular forces between layers.
  • One delocalised electron per carbon atom.
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11
Q

Describe and explain the properties of graphite

A
  • Graphite is soft / slippery because there are only weak intermolecular forces between layers which allow the layers to slide over one another.
  • Graphite conducts electricity because there is one delocalised electron per carbon atom. The delocalised electrons are mobile charges.
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12
Q

Describe the structure of diamond

A
  • All carbon atom are covalently bonded to four other carbon atoms.
  • No delocalised electrons.
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13
Q

Describe the properties of diamond

A
  • Very hard.
  • Very high melting point.
  • Doesn’t conduct electricity as there are no charged particles.
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14
Q

What are the uses of graphite? Why?

A
  • Electrodes because graphite conducts electricity and has a high melting point.
  • Lubricant because it’s slippery (the layers in graphite can slide over each other).
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15
Q

Why is diamond used in cutting tools?

A

It’s very hard.

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16
Q

What is a fullerene?

A

A fullerene is a molecule made of carbon, shaped like a closed tube or hollow ball.

17
Q

Name two fullerenes

A

Graphene

C60 (buckminsterfullerene)

18
Q

What are the properties of the fullerene C60?

A
  • Slippery due to weak intermolecular forces.
  • Low melting point.
  • Spherical.
  • Strong covalent bonds between carbon atoms in a molecule.
  • Large surface area.
19
Q

What are the properties of graphene?

A
  • High melting point due to covalent bonding between carbon atoms.
  • Conducts electricity because it has delocalised electrons.
20
Q

Why is graphene useful in electronics?

A
  • It is extremely strong and has delocalised electrons which are free to move and carry charge.
  • It is only one atom thick as it is a single layer of graphite.
21
Q

What is a polymer? Name a polymer

A
  • Long chain molecules formed from many monomers.
  • E.g. poly(ethene)
22
Q

Draw the structure of poly(ethene)

A
23
Q

What bond is formed between carbon atoms in polymer molecules?

A

Covalent bonds

24
Q

What are the properties of metals?

A
  • High melting point.
  • High density.
  • Good conductors of electricity.
  • Malleable and ductile.
  • Generally shiny.
25
Q

Explain why metals are malleable

A

The atoms are arranged in uniform rows which can slide over one another.

26
Q

Explain why metals can conduct electricity

A

The electrons in the metal are charges that can move.

27
Q

What are the general properties of non-metals?

A
  • Low boiling points.
  • Poor conductors of electricity.
  • Brittle when solid.

Chemistry (My Flashcards) (17 decks)

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