Ch1: Experimental Chemistry

Question 1

A mixture is made up of…

Answer 1

Two or more substances that are not chemically combined

Question 2

Air’s density

Answer 2

32
O2 –> (Mr (16) x (2))

Question 3

To separate a mixture of two solids, we use a solvent in which one solid is _______ (The other is _______ in that ______)

Answer 3

soluble and insoluble in that solvent

Question 4

substances can turn straight into a gas on heating, without becoming a liquid first
what is this called?

Answer 4

sublimation

Question 5

A pure substance is made up of…

Answer 5

One single element or compound. It is not mixed with any other substance.

Question 6

A mixture is made up of..

Answer 6

Two or more substances that are not chemically combined together

Question 7

Some substances can turn straight into gas on heating, without becoming a liquid first. This is called….

Answer 7

Sublimation

Question 8

Sublimation is used to separate a solid that….. from one that does not.

Answer 8

Sublimes.

Question 9

Sublimation can he used to separate____ mixtures such as….

Answer 9

Solid-solid, ammonium chloride and sodium chloride.

Question 10

Sublimation test:
A mixture is placed in an evaporating dish with an inverted funnel on the top. It is then gently _____.
The ammonium chloride _____ and changed directly to a _____ which _____ back to a ______on the cold glass funnel.
What remains in the evaporating dish?

Answer 10

Heated
Sublimes, gas, cools
Sodium chloride

Question 11

A mixture made of solid particles of different sied can be separated by….

Answer 11

Sieving

Question 12

…….. can be used to separate a magnetic substance from a non-magnetic substance.

Answer 12

Magnetic attraction

Question 13

Meaning of the term ‘solute’
E.g. …..

Answer 13

Substance that dissolves ______.

Question 14

The liquid that the substance dissolves in

Answer 14

Solvent

Question 15

Characteristics of solutions

Answer 15

Clear. Some may be coloured (e.g. brown, blue, green) or have no colour (colourless)

Question 16

Filtration is used to separate an…… from a liquid. a funnel lined with filter paper is usually used.

Answer 16

Insoluble solid

Question 17

……. is used to separate a soluble solid from a liquid.

Answer 17

Evaporation

Question 18

……. is a process of obtaining a soluble solid from a solution by heating the solution until all the water has boiled off

Answer 18

Evaporation to dryness

Question 19

Process of evaporation to dryness

Answer 19

Obtaining a soluble solid from a solution by heating the solution until all the water has boiled off

Question 20

If we heat the solution so that only some of the solvent vaporises, and then leave the hot saturated solution to cool, some of the solid reappears as pure …….
this is called……

Answer 20

Crystals, crystalization

Question 21

Simple distillation is used to separate the …….(liquid) from a solution

Answer 21

Solute

Question 22

Boiling chips are added to

Answer 22

Ensure smooth boiling

Question 23

As the solution boils, vapour rises. If distillation is allowed to carry on, ……

Answer 23

a solid residue of the salt will be left in the flask

Question 24

The condensed water in simple distillation in the conical flask is called the….

Answer 24

Distillate

Question 25

The separating funnel is used to....

Answer 25

Separate two liquids which do not mix together

Question 26

Mixtures that do not mix together are...

Answer 26

Immiscible

Question 27

In the separating funnel, when the tap is opened, what drained?

Answer 27

The densest layer is allowed to drain into the beaker.

Question 28

Process of separating a mixture of miscible liquids which dissolve in ......

Answer 28

Chromatography, same solvent

Question 29

Process of separating dyes in food colouring, ink or pigments

Answer 29

Paper chromatography to a chromatogram

Question 30

Some solutes are less soluble in the solvent and thus does not travel very far across the paper. What does this show?

Answer 30

Difference in solubility allowing the dyes in the food colouring to be separated

Question 31

Process of separating a mixture of miscible liquids with different boiling points.

Answer 31

Fractional distillation

Question 32

In fractional distillation, explain what is happening in the fractionating column

Answer 32

The liquid with the lower boiling point passes into the condenser. Higher boiling point condenses and falls back into the flask.

Question 33

What does presence of impurities do to the melting points?

Answer 33

Increases the melting points, causing the substance to melt over a range of temperatures.

Question 34

Suitable drying agent for carbon dioxide

Answer 34

Fused calcium chloride.

Question 35

Suitable drying agent for Ammonia

Answer 35

Quicklime (calcium oxide)

Question 36

Suitable drying agent for Hydrogen

Answer 36

Fused calcium chloride

Question 37

Fused calcium chloride. It readily absorbs moisture from the air, So it must be...

Answer 37

Freshly heated before use

Question 38

Quicklime (calcium oxide) absorbs moisture and carbon dioxide from the air, so it must be...

Answer 38

Freshly heated before use