Planet Earth Flashcards

1
Q

what is decantation

A

Decantation is a process to separate mixtures by removing a liquid layer that is free of a precipitate, or the solids deposited from a solution.
eg. sand from water

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2
Q

how to determine a saturated solution

A

remove a drop of solution with glass rod

see whether solids form when drops cool

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3
Q

why cold water is used to wash a crystal after crystallization

A

remove water-soluble im purities

help reduce loss of salt

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4
Q

principle of simple distillation

A

water boils at 100.C but salts are non-volatile

steam formed condenses

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5
Q

how to obtain dilute H2SO4 from concentrated H2SO4

A

concentrated sulphuric acid is added slowly into a large amount of water with constant stirring

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6
Q

what is the function of the glass beads in the fractionating column

A

to provide a large surface area for condensation and evaporation of the mixture.

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7
Q

daily application of neon

A

Gas for filling neon lights

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8
Q

outline the underlying principle of simple distillation experiment

A

Water boils at about 100oC , but the salts in sea water are non-volatile
The steam formed condenses on the cold surface of the condenser to give liquid water.

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9
Q

sodium is….

A

highly reactive

corrosive

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10
Q

what is quicklime

A

CaO

Calcium oxide

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11
Q

what is slaked lime

A

Ca(OH)2

Calcium hydroxide

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12
Q

what is limewater

A

saturated calcium hydroxide solution

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13
Q

what will thermal decomposition of metal carbonate give out

A

metal oxide and carbon dioxide

endothermic

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14
Q

is sodium corrosive

A

yes

as it is alkali metal

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15
Q

is conc. aqeous ammonia corrosive?

A

yes

as it is concentrated altho it is weak base

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16
Q

fractional distillation of liquid air products

A
  • 183 O2
  • 186 Ar
  • 196 N2
17
Q

advantage of using microscale experiment

A

save cost on chemicals
minimize chemical hazard
reduce chemical waste

18
Q

what are the sources of CaCO3

A

marble
limestone
chalk
egg shells

19
Q

state one natural source of silicon dioxide

A

sand/quartz

20
Q

state one industrial use of silicon dioxide

A

to make glass

21
Q

using the same amount of reactant, suggest how to increase the volume of liquid collected using the delivery tube and a test tube

A

immerse the test tube into a ice water bath to enhance the cooling effect

22
Q

what is relative isotopic mass

A

relative isotopic mass of an isotope of an element Is the mass of the atom on the C=12 scale

relative isotopic mass= mass of an atom of the element/ (1/12)(mass of an atom of carbon 12)

23
Q

what is relative atomic mass

A

relative atomic mass of an element is the average isotopic mass of all natural isotopes on the C=12 scale

24
Q

Aluminium is the most abundant element in the earth’s crust

T/F

A

F
its is the most abundant metal > Fe
but < O/N

25
Q

When distinguishing substance which are solids

Need to do what first

A

Dissolve the substance in deionised water first

26
Q

what is saturated solution

A

a solution containing the maximum amount of solute at a specific temperature