C2 - Structure & Properties Flashcards

0
Q

Why do ionic compounds conduct electricity when melted or dissolved in water?

A

Their ions can move freely and carry charge through the liquid.

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1
Q

Why do ionic compounds have high melting points?

A

It takes a lot of energy to break the many strong ionic bonds which hold the giant lattice together.

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2
Q

Which types of substances have low boiling points?

A

Substances made up of simple molecules.

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3
Q

Why do some substances have low boiling points?

A

The intermolecular forces between simple molecules are weak.

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4
Q

Why don’t simple molecules conduct electricity?

A

Simple molecules have no overall charge so cannot carry electrical charge.

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5
Q

What boiling points do giant covalent structures have?

A

High boiling points

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6
Q

Why is graphite soft and slippery?

A
  • It contains layers of covalently bonded carbon atoms.
  • There are no covalent bonds between the layers.
  • The layers can slide over each other.
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7
Q

Why can graphite conduct electricity?

A

There are delocalised electrons along the layers.

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8
Q

What are fullerenes?

A

Large cage like structures based on hexagonal rings of carbon atoms.

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9
Q

Why does graphite have delocalised electrons?

A

Each carbon only forms three covalent bonds out of a possible four leaving a spare electron.

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10
Q

Give two possible uses of fullerenes.

A
  • Delivering drugs to a specific part of the body.

- Catalyst and lubricant

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11
Q

Why is it possible to bend and shape metals?

A

The layers of atoms/ions in a giant metallic structure can slide over each other.

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12
Q

Why do metals allow electricity and heat to pass through?

A

Delocalised electrons allow electricity and heat to pass through more easily.

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13
Q

What are shape memory alloys?

A

An alloy that, if deformed, can return to its original shape on heating.

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14
Q

Why are alloys harder than pure metals?

A

There are different sized atoms making it more difficult for the layers to slide.

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15
Q

What do the properties of a polymer depend on?

A
  • The monomers used to make it.

- The conditions of the reaction.

16
Q

How is LDPE formed?

A

Ethene reacts under very high pressure and a trace of oxygen.

17
Q

How is HDPE formed?

A

Using a catalyst at 50C and a slightly raised pressure.

18
Q

What is a thermosoftening polymer?

A

A polymer that softens when heated and is made up of individual polymer chains tangled together.

19
Q

What are thermosetting polymers?

A

Polymers which don’t melt when heated and have strong covalent bonds forming cross links between polymer chains.

20
Q

What is nano science?

A

The study of small particles between 1and 100 nanometers in size.

21
Q

Give seven possible uses of nano technology in the future.

A
  • Self-cleaning glass
  • Modern sun screens
  • Cosmetics that are absorbed deeper into the skin.
  • Delivery of drugs in the body
  • Cancer treatment
  • Nano-tech electronics
  • Nanotechnology military suits
22
Q

Explain how nano technology can be used in cancer treatment.

A
  • Nano gold particles can be injected and absorbed by tumours.
  • Tumours have thin leaky blood vessels allowing the gold nano particles to enter without going into healthy cells.
  • A laser heats the gold which heats the tumour cells but not surrounding cells.
23
Q

Give two disadvantages of using nanotechnology in medicine.

A
  • They have a large surface area meaning a spark could trigger an explosion.
  • Nanoparticles could enter the bloodstream causing damage.