U10 - Giant covalent structures

Question 1

What are large three dimensional structures held together by

Answer 1

single covalent bonds joining the atoms together in giant covalent
structures

Question 2

Macromolecules can be divided into two types

Answer 2

Giant covalent
polymers

Question 3

Describe diamond structure

Answer 3

*each carbon atom is joined to 4 other carbon atoms by covalent bonds.
*difficult to break
*high melting and boiling point
*heated in air, they start reacting
with the oxygen forming CO2
*do not conduct electricity

Question 4

What are diamonds used for

Answer 4

*cutting and drilling.
*in jewellery because they have a high refractive index when
cut and polished

Question 5

Describe graphite structure

Answer 5

*allotrope of carbon
*black in colour
*bonded covalently to three other carbon atoms, forming
hexagonal layers
*high melting point
*soft and flaky

Question 6

Uses for graphite

Answer 6

lubricant
pencil lead.

Question 7

Structure of silicon

Answer 7

*found a s silicon dioxide, quartz
and sand
*bonded onto 4 oxygen atoms and
each oxygen atom is bonded onto two silicon atoms
*forming a large covalent structure
*high melting and boiling point
*covalent bonds

Question 8

Properties of Diamond and silicon dioxide

Answer 8

*Clear crystals
*Very hard
*High melting point (must break covalent bonds to separate the atoms)
*Poor conductors of electricity and heat. They have no free electrons that can
*carry the charge.