separating techniques Flashcards

(38 cards)

1
Q

Something that CAN dissolve is described as being…

A

soluble

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2
Q

How much of something that can be dissolved is called…

A

solubility

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3
Q

Something that CANNOT be dissolved is described as being…

A

insoluble

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4
Q

A technique used to separate a solvent from a solution

A

distillation

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5
Q

The solid that will be dissolved, is the…

A

solute

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6
Q

The mixture of solute and solvent is called the…

A

solution

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7
Q

The liquid that the solute will be dissolved into is the…

A

solvent

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8
Q

what does filtration separate

A

insoluble solids from liquids

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9
Q

definition of pure

A

a substance made of 1type of element/compound

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10
Q

how to separate a liquid and dissolved solid -

A

evaporation

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11
Q

how to separate more than two liquids

A

distillation

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12
Q

how to separate two coloured liquids

A

chromatography

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13
Q

Chromatography is used to…

A

separate mixtures of coloured or non-coloured substances that are soluble in the same solvent

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14
Q

How does chromatography separate inks on paper?

A

-The water is drawn up by capillary action (attraction between water molecules and paper).
-When the solvent reaches the ink spots, they are dissolved and carried up the paper.
-The most soluble ink travels the furthest, while the less soluble inks stay closer to the bottom.

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15
Q

how to filter something

A

-filter out by using filter paper and a funnel

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16
Q

how to turn rock salt into pure salt

A

-filtration and evaporation
-step 1: grind rock salt mixture so it can filter easier
-step 2: add 50ml of water into the mixture and mix
-step 3: use a funnel and filter paper to filter (the liquid/salt solution goes through but the solid/rocks don’t)
-step 4: heat the salt solution in an evaporating basin, the water evaporates leaving pure salt crystals behind

17
Q

When is distillation used as a separating technique?

A

when separating a liquid from a solution or a mixture that have different boiling points

18
Q

explain how distillation works

A

-heating the mixture —> when you heat a liquid mixture, the particles start moving faster - breaking the force of attraction between the particles to form a gas. The liquid with the lower boiling point will then turn into gas first because the particles need less heat to break the intermolecular force between the particles.
-evaporation —> the liquid that boils first evaporates because the particles have enough kinetic energy to break the force between the particles
-condensation —> the gas is then cooled down in the condenser. As it cools, the gas particles lose energy therefore cannot break the bond, leading to bonds created. This leads to it condensing. The separated liquid is then collected in a new container

19
Q

What is the name given for the pencil line?

20
Q

Why should we use pencil for the baseline rather than pen?

A

Pen ink would dissolve in the solvent and move up the paper, whilst pencil is insoluble so won’t interfere

21
Q

What are some solvents commonly used in chromatography?

A

water, ethonal

22
Q

What is the name of the resulting paper we end up with? (chromatography)

A

A chromatogram

23
Q

what does the ‘mobile phase’ refer to

A

the molecules that can move

24
Q

Which is the mobile phase in paper chromatography?

25
The 'stationary phase' refers...
the molecules that can't move
26
Which is the stationary phase in paper chromatography?
the paper
27
how to calculate rf value
distance moved by spot / distance moved by solvent
28
in filtration explain why solid c separated from the mixture of c and d
solid c is insoluble whereas d is soluble
29
What is the name given to a reaction which causes the temperature to increase?
exothermic
30
The student repeated the experiment with 1.2 g of copper and 50 cm of zinc sulfate solution. The temperature did not increase. Give one reason why.
copper is less reactive than zinc, so it can’t react with zinc sulfate
31
The temperature of the solution increases when zinc reacts with copper sulfate solution. Give two other observations that can be made when zinc reacts with copper sulfate solution
-becomes colourless (colour change) -solid produced
32
Why does producing drinking water from sea water using distillation cost a lot of money?
uses a lot of energy
33
River water is filtered then sterilised to make drinking water. Why are these two processes done?
Filtering-removes particles/solids sterilising- kills bacteria
34
(chromatography) Explain why the some colours don’t move from the start line.
they are insoluble so do not move with the solvent
35
there were four coours in the printer ink. (c) Suggest one reason why only three colours were visible on the chromatogram.
-two dyes may have the same Rf value
36
Suggest now ire student could use chromatography to show there were four colours in the printer ink.
use a different solvent
37
What is the name given to a mixture that has been designed as a useful product?
formulation
38
What would the student have used to draw the start line? (chromatography) and why
pencil, so the start line doesn’t dissolve in the solvent