paper 6 Flashcards

1
Q

suggest why an excess of sodium sulfate is added to the water in the beaker

A

to ensure a saturated solution is formed

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2
Q

suggest why the mixture in the beaker was stirred as it was heated

A

to speed up reaction

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3
Q

explain why the temperature change decreases towards the end of each expirment

A

solution has been used up

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4
Q

explain why the results obtained would be different if a polystyrene cup is used instead of the beaker

A

temp is higher, less heat is lost to surroundings

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5
Q

explain an advantage and disadvantage of using a burette instead of measuring cylinder

A

more accurate readings
takes more tie to add solution

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6
Q

color of metals

A

grey

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7
Q

color copper

A

brown

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8
Q

copper oxide

A

black

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9
Q

copper salts color

A

blue except copper carbonate green

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10
Q

mineral acids and alkalis

A

colourless

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11
Q

hydrocarbos burn

A

with smoky flame

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12
Q

nitrogen dioxide

A

brown gas

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13
Q

barium sulfate

A

white ppt

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14
Q

spatula

A

scoop powder

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15
Q

burette and volumetric pippete

A

more accurate
slower to add solution
pipette only 25 cm3 possible

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16
Q

measuring cyclinder

A

faster measurments less accurate

17
Q

why is crystalisation used

A

seperate soluble solids from solution

18
Q

why is oil bath used in fractona distillation

A

if solution has boiling point higher than water

19
Q

how can you produce solbule salts

A

titration or acid and excess solid

20
Q

insolbule salts

A

precipitation

21
Q

white tile titration

A

more vivid color change

22
Q

litmus paper

A

red acid, blue alkaline

23
Q

phenolthalein

A

pink acid, blue alkaline

24
Q

methyl orange

A

red acid, yellow alkaline

25
Q

how can you collect gas with water danger

A

if gas insoluble in water
if heating remove delivery tube first to avoid cracking

26
Q

why is sukfuric acid used

A

to dry gas except ammonia

27
Q

why dont you over heat crystallisation

A

not produce dry powder salt, as you want hydrated salts

28
Q

crystalisation point

A

place galss rod, crystals formed

29
Q

precipitation why do you put water

A

insoluble= remove soluble impuraties
soluble= collect all salt

30
Q

cotton wool why used

A

allow gas to leave
avoid spilling of acid