Cosas Que Tengo Que Saber

Question 1

State what is meant by the term electrolysis?

Answer 1

Breakdown of an ionic compound molten or dissolved using electricity

Question 2

State what is meant by the term equilibrium?

Answer 2

When the rate of both the forward and backwards reaction are equal and the reaction is happening at a constant concentration

Question 3

Give the name used to describe a “family” of similar compounds with the same general formula, similar chemical properties and the same functional group.

Answer 3

Hermologous series

Question 4

State the colour change observed when propane is added to aqueous bromine

Answer 4

From orange to colourless

Question 5

Describe a test for oxygen

Answer 5

Test: glowing splint
Observations: It relights

Question 6

Describe a test for hydrogen

Answer 6

Test: put a lit splint
Observations: it will make a squeaky pop

Question 7

Test for chlorine gas

Answer 7

Test: damp blue litmus paper
Observations: bleaches

Question 8

Test for carbon dioxide

Answer 8

Test: limewater
Observations: turns cloudy white and milky

Question 9

Test for ammonia

Answer 9

Test: damp red litmus paper
Observations: turns blue

Question 10

General formula of carboxylic acids

Answer 10

CnH2n+1COOH

Question 11

General formula of alcohols

Answer 11

CnH2n+1OH

Question 12

General formula of alkenes

Answer 12

CnH2n

Question 13

General formula of alkanes

Answer 13

CnH2n+2

Question 14

Test for sulphur dioxide

Answer 14

Turns acidified aqueous potassium manganate from purple to colourless

Question 15

State the meaning of the term base

Answer 15

Proton acceptor

Question 16

State the meaning for the term acid

Answer 16

Proton donor

Question 17

State what is meant by the term catalyst

Answer 17

Something that speed up the rate of reaction without being used up

Question 18

State general characteristics of hermologous series

Answer 18

• general formula
• chemical properties
• functional group

Question 19

Ionic bond

Answer 19

Electrostatic attraction between oppositely charged ions

Question 20

Avogadros number

Answer 20

6.02 x 10^23

Question 21

Mass=

Answer 21

Mr x mol

Question 22

Percentage yield=

Answer 22

Actual yield over theoretical yield x 100

Question 23

Number of moles (vol, conc)

Answer 23

volume of solution x Concentration (in mol/dm^3)

Question 24

Volume of a gas (dm^3) =

Answer 24

Moles of gas x 24

Question 25

Percentage purity =

Answer 25

Pure yield/ total impure yield x100

Question 26

Percentage composition by mass =

Answer 26

Mr of element that is asked/ mr of total compound x100

Question 27

Electroplating:

Answer 27

Anode: metal Cathode: object Electrolyte: contains metal ions of the metal you are plating (eg silver nitrate)

Question 28

Exothermic reactions

Answer 28

More energy is needed to make the bonds in the products than to break the bonds in the reactants

Question 29

Endothermic

Answer 29

More energy is needed to break the bonds in the reactants than is to make the bonds in the products

Question 30

Activation energy

Answer 30

The minimum amount of energy required for a reaction to occur

Question 31

Redox is

Answer 31

When oxidation and reduction occur at the same time

Question 32

Reducing agents

Answer 32

Cause other substances to be reduced, therefore they themselves are oxidised

Question 33

Oxidising agents

Answer 33

Cause other substances to oxidise, therefore they themselves are reduced

Question 34

Group 1 metals are called

Answer 34

Alkali metals

Question 35

Group 7 elements are called

Answer 35

Halogens

Question 36

Fluorine is a

Answer 36

Yellow gas

Question 37

Chlorine is a

Answer 37

Green gas

Question 38

Bromine is a

Answer 38

Red/brown liquid

Question 39

Iodine is a

Answer 39

Grey solid

Question 40

Sublimation

Answer 40

When a solid turns directly into a gas

Question 41

Where does carbon dioxide come from

Answer 41

Complete combustion of fuels (plentiful O2)

Question 42

Where does carbon monoxide come from

Answer 42

Incomplete combustion of fuels (insufficient O2)

Question 43

Where does methane come from

Answer 43

- waste gases from digestion of animals - decomposition of vegetation

Question 44

Where do oxides of nitrogen come from

Answer 44

-high temp in car engines cause O2 and N2 to react

Question 45

Where does sulfur dioxide come from

Answer 45

Sulfur impurities in crude oil

Question 46

Consequences of carbon dioxide

Answer 46

-enhanced greenhouse effect -> global warming -> climate change + extinction of species

Question 47

Consequences of methane

Answer 47

-enhanced greenhouse effect -> global warming -> climate change + extinction of species

Question 48

Consequences of carbon monoxide

Answer 48

Toxic gas -> combines irreversibly with red blood cells

Question 49

Consequences of oxides of nitrogen

Answer 49

-acid rain -respiratory problems -photochemical smog

Question 50

Consequences of sulfur dioxide

Answer 50

-acid rain

Question 51

Consequences of particulates

Answer 51

- respiratory problems + cancer

Question 52

Use of alcohols

Answer 52

-alcoholic drinks -perfumes (they are good solvents) -fuels

Question 53

Rf value=

Answer 53

Distance traveled by component/ distance traveled by solvent

Question 54

Define a Redox reaction

Answer 54

Where oxidation and reduction occur at the same time

Question 55

State how a student knows that a suitable number of results have been obtained

Answer 55

When he has obtained at least 2 results that are within 0.2 or less

Question 56

State observations that indicate that ……………. Is in excess

Answer 56

- no more ……………. Can dissolve - no more bubbles

Question 57

Give a reason why the rate of reaction increases when using powder

Answer 57

Because tha powder has a larger surface area, therefore more area is able to react at the same time so there are more collisions per unit time so there is an increase in rate of reaction

Question 58

State differences in the physical properties of group 1 elements and transition metals

Answer 58

- group 1 elements have lower melting points -group 1 metals are softer -transition metals are denser

Question 59

Explain why chlorine does not react with aqueous sodium fluoride

Answer 59

Because fluorine is more reactive than chlorine

Question 60

Suggest why …………. Might be done in an atmosphere of argon and not in air.

Answer 60

Reacts with oxygen and argon is inert

Question 61

Explain how this chemical equation shows that ……………. Is acting as a reducing agent

Answer 61

………………. is oxidised

Question 62

Reaction of metal and water

Answer 62

Metal + water -> metal hydroxide +hydrogen