Topic 2 - States of matter and nanoparticles

Question 1

What three things do the forces of attraction between particles in a material depend on?

Answer 1

• meterial
• temperature
• pressure

Question 2

Solids?

Answer 2

• strong forces of attraction between particles - holds them close together in fixed positions - form regular lattice arrangement
• particles dont move from positions - all solids keep definite shape and volume - dont flow
• particles vibrate about their positions - hotter solid becomes - more they vibrate

Question 3

Liquids?

Answer 3

• weak forces of attraction between particles - randomly arranged + free to move past each other - tend to stick closely together
• definite volume - dont have definite shape - flow to fill bottom of container
• particles constantly moving with random motion - hotter liquid gets - faster they move - expand slightly

Question 4

Gases?

Answer 4

• forces of attraction between particles very weak - free to move + far apart - travel in straight lines
• dont take difinitive shape or volume - always fit into any container
• move constantly with random motion - hotter gas = faster moving particles
• gases expand when heated - or when pressure increases

Question 5

What does aqueous mean?

Answer 5

dissolved in water

Question 6

Types of particle?

Answer 6

• coarse particles - diameter between 2500nm and 10000nm - also called dust
• fine particles - diameter between 10nm and 2500nm
• nanoparticles - diamter between 1 and 100nm - particles only contain a few hundred atoms

Question 7

Uses of nanoparticles?

Answer 7

• huge surface area to volume ratio - could help to make new catalysts
• nanomedicine - idea that tiny particles such as fullerenes - absorbed more easily by body than most particles
• this means they can deliver drugs right into the cells
• some conduct electricity - can be used in tiny electric circuits for computer chips
• silver nanoparticles - antibacterial properties - added to polymer fibres - then used to make surgical masks and wound dressings - also added to deodorants

Question 8

How are nanoparticles used in suncream?

Answer 8

• nanoparticles of zinc oxide or titanium dioxide block UV rays better than traditional suncreams
• better skin coverage than traditional suncreams

Question 9

Effects of nanoparticles?

Answer 9

• Nanoparticles are not fully understood
• possible health risks if inhaled or absorbed through skin
• potential risk to aqua life and ecosystems when washed away