Solutions and gases

Question 1

Solid particle arrangement

Answer 1

• regular
• very close
• vibrate around a fixed position

Question 2

liquid particle arrangement

Answer 2

-close
-randomly arranged
-move around eachother

Question 3

gas particle arrangement

Answer 3

• far apart
• randomly arranged
• move fast in all directions

Question 4

why do liquids and gases take the shapes of their containers

Answer 4

they flow

Question 5

why can gases be squashed easily

Answer 5

theyre widely spaced and randomly arranged

Question 6

explain how solids melt using particles

Answer 6

• energy makes the particles vibrate more quickly
  -overcome some of the force of attraction between particles
  -solid melts

Question 7

why does temperature not rise during changes of state (condensation melting etc)

Answer 7

the energy supplied is being used to overcome the force of attraction holding the particles together

Question 8

explain how a liquid boils with particles

Answer 8

• particles move around each other more rapidly in all directions
  -when boiling point reached particles have enough energy to overcome the remaining force holding them together as a lattice

Question 9

soluble in water

Answer 9

-all potassium sodium and ammonium salts
-all nitrates
-all common halides (chlorides bromides iodides) EXCEPT silver and lead
-all common sulfates except lead calcium and barium

Question 10

insoluble in water

Answer 10

all common carbonates except ASP (ammonium sodium and potassium)

all common hydroxides except ASP

Question 11

the history of the athmosphere

Answer 11

1. volcanic eruptions gave the atmosphere lots of co2 + h2o gas
2. earths temperature falls to 100c, first rain falls. no oxygen, co2 dissolves into seas
3. first plants evolve, photosynthesis decreases co2 increases o2

4.first animals evolve, die sink to the bottom of sea and covered in sediment

5. dead animals and plants become fossil fuels , coal oil gas co2 locked away

6.400 millions later atmosphere same as today

Question 12

percentage of gases in todays atmosphere

Answer 12

N2 - 78 %
O2 - 21 %
Ar - 1%
Co2 - 0.04%

Question 13

describe two reasons co2 decreased

Answer 13

dissolved into oceans
primitive plants used it for photosynthesis

Question 14

explain why doing repeats is helpful

Answer 14

increases accuracy , identify and remove anomalous results

Question 15

why wait for apparatus to cool before reading volume of air in gas syringe

Answer 15

gases expand