Chem chp1

Question 1

How many methods for collecting gases are there?

Answer 1

4

Question 2

What are the methods for gas collection?

Answer 2

Water displacement, Downward delivery, Upward delivery, using gas syringe

Question 3

What is Water displacement used for?

Answer 3

To collect insoluble or slightly soluble gases.

Question 4

Does density affect Water displacement gas collection?

Answer 4

No

Question 5

What is Downward delivery gas collection method used to collect?

Answer 5

Gases denser than air and soluble in water

Question 6

Is the gas jar sealed during downward delivery？

Answer 6

No

Question 7

What is upward delivery used for?

Answer 7

To collect air less dense than air and soluble in water.

Question 8

Is gas jar sealed during upward delivery?

Answer 8

No

Question 9

What is use of gas syringe collection method used for?

Answer 9

To measure and collect any type of gas.

Question 10

How many drying agents for gases are there?

Answer 10

3

Question 11

What should concentrated sulfuric acid be used for?

Answer 11

To dry acidic gases

Question 12

What should quicklime drying agent be used for?

Answer 12

To dry alkaline gases

Question 13

How does quicklime dry the gas?

Answer 13

It absorbs moisture and carbon dioxide from air

Question 14

What is another name for fused calcium chloride?

Answer 14

Anhydrous calcium chloride

Question 15

What is fused calcium chloride used for?

Answer 15

To dry neutral gases

Question 16

How does fused calcium chloride dry the gas?

Answer 16

It absorbs moisture from air

Question 17

Which 2 drying agents have to be freshly heated before use?

Answer 17

Quicklime and Fused calcium chloride

Question 18

Define mixture

Answer 18

A substance that is made up of two or more substances that are not chemically combined

Question 19

What is a pure substance made up of?

Answer 19

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

Question 20

What are the different types of mixtures?

Answer 20

Liquid-liquid, solid-solid, solid-liquid.

Question 21

What separation techniques can be used on solid-solid mixtures?

Answer 21

Magnetic attraction, sieving, using solvents, sublimation

Question 22

What separation techniques can be used on solid-liquid mixtures?

Answer 22

Filtration, evaporation to dryness, crystallisation, simple distillation

Question 23

What separation techniques can be used on liquid-liquid mixtures?

Answer 23

Using separating funnel, chromatography, fractional distillation

Question 24

Define solvent

Answer 24

A liquid that dissolves solids (solute)

Question 25

Define solute

Answer 25

Solids that dissolve in solvent.

Question 26

Define solubility

Answer 26

The ability of a solute to dissolve in a solvent

Question 27

Define sublimation

Answer 27

A process in which a substance changes from a solid to gas without passing through the liquid state

Question 28

Describe the sublimation experiment

Answer 28

Solid sublimes into gas-> moves away form mixture Cool surface provided-> gas changes back to solid

Question 29

In filtration, what do you call the mixture collected in the beaker?

Answer 29

The filtrate

Question 30

In filtration, what do you call the solid that remains on the filter paper?

Answer 30

Residue

Question 31

What are miscible liquids?

Answer 31

Liquids which form a **uniform (/homogenous)** solution when mixed together

Question 32

What is a heterogenous mixture?

Answer 32

A mixture which contains **immiscible liquids **that **do not form a uniform solution**.

Question 33

What do you call the layers which immiscible liquids separate into?

Answer 33

Phases

Question 34

What does Rf value stand for?

Answer 34

Retention factor

Question 35

What is Rf value refer to in a substance?

Answer 35

The measure of the substance's solubility in a solvent.

Question 36

What is the formula for Rf value?

Answer 36

distance travelled by substance/ distance travelled by solvent

Question 37

What is the difference between fractional distillation and simple distillation?

Answer 37

Fractional distillation is used to separate two miscible liquids with different boiling points, while simple distillation is used to separate a pure solvent from a solution.

Question 38

What are the three ways to test for purity of substances?

Answer 38

Melting point of solid, boiling point of solid, chromatography.

Question 39

What happens to melting and boiling point when containing impurities?

Answer 39

Melting point decrease, boiling point increase