C5 Chemical Changes

Question 1

What is an oxidation reaction?

Answer 1

An reaction where something gains oxygen

Question 2

What does “it has been oxidised mean”?

Answer 2

When it has gained oxygen

Question 3

What does it mean if something has been reduced?

Answer 3

It has lost oxygen

Question 4

What the PH scale?

Whta is a neutral (number

What is a low or high called

Answer 4

It measires how acidic somethig is

Goes from 0-14

The lower it is the more acidic it is

The higher it is the more alkaline it is

A neutral substance is a 7

Question 5

What is the universla indicator?

Answer 5

Something (based on colors) that when added to a solution will react to form a colour which can be checked to see what acidity it is

Question 6

How else could you calucate the acidity of something?

Answer 6

Using a PH probe

Question 7

What is an acid?

Answer 7

A substance that formes an aq solution with a ph less that 7

Question 8

What is an alkali??

Answer 8

A base that disloves in water tp form a solition with a PH value of more than 7 and which forms OH- ions in water

Question 9

Give the reaction between acids and base:

Answer 9

Acid+Base = Salt+Water

Or it could be said like this

H+(aq) + OH-(aq) = H*2O(l)

Question 10

What do acids produce in water?

Answer 10

Protons

Hydrogen ions (which is the same as a proton)

Question 11

What dp acids do in a aq solution?

Answer 11

They ionise

Question 12

Of an alkali as solution reacts with a acid then what is alwayes formed

Answer 12

OH-ions

Question 13

What is the equation for neutralisation?

Answer 13

H+(aq)+ OH-(aq)=H2O(l)

Question 14

Acid+Alkali

Answer 14

Acid+Alkali=Salt + Water

Question 15

Acid+Metal carbonate

Answer 15

Acid+Metal carbonate = Salt+ Water+Carbon Dioxide

Question 16

What is a PH probe?

Answer 16

Attacked to a PH meter it can also measure the PH of a substance electronicly and really acuratly. It will give you a number.

Question 17

What do acids produce in water?

Answer 17

They ionise in an aq solution and produce H+ ions

Question 18

What happens when a strong acid meets water?

Answer 18

It ionise completely. All the acid particles dissociate to release H+ ions

Question 19

Give 3 examples of a strong acid?

Answer 19

Sulfuric, hydrochloric and nitric acids

Question 20

What happens when a week acid meets water?

Answer 20

It doesn’t fully ionise. Only a small portion of the acid particles dissociate to release H+ ions

Question 21

Give 3 examples of a week acid?

Answer 21

Ethanoic, citric and carbonic acids

Question 22

When a week acid is ionised can it be reverced?

When a strong acid is ionised can it be reverced?

Answer 22

Yes as only a few of the acid particles ionised

No as all of the acids ionised

Question 23

Why are strong acids more reactive than week acids?

Answer 23

The reaction is with H+ ions and other substances. So if the concentration of H+ ions is bigger (eg in strong acids) then there will be a quicker and more reactive

Question 24

What exactly is the PH of a substance measuring?

Answer 24

The amout of H+ ions in a solition

Question 25

If PH decrease by 1 what happenes to the amount of H+ ions?

Answer 25

They have increased by a factor of 10

Question 26

If PH decrease by 2 what happenes to the amount of H+ ions?

Answer 26

They have increased by a factor of 100

Question 27

If they have the same concentration what do we know about the PH's of week and strong acids?

Answer 27

The PH of a strong acid is always less than a weeker acid

Question 28

What does the strength of an acid tell you?

Answer 28

What proportion of the acid molecules ionised into the water

Question 29

What does the concentration of an acid tell you?

Answer 29

How much acid there is in a certian volume of water | How watered down the acid is

Question 30

When will the concentration of the acid be at the highest?

Answer 30

When there is a high amount of acid in a small amount of water

Question 31

When will the concentration of the acid we at it's weekest?

Answer 31

When there is little acid molecules in a large volume of water

Question 32

When will PH decrease? (concentration)

Answer 32

PH will decrease when the acid concentration increases westher it is a strong or weak acid

Question 33

What is a base?

Answer 33

Something that ends in oxide or hydroxide

Question 34

What is a alkli

Answer 34

A base that is disolved in water

Question 35

Give the equasion between an acid and a carbonate?

Answer 35

Acid + (Metal) Carbonate = Salt + Water + Carbon dioxide

Question 36

Is it possible to make an soluable salt using an insoluable base?

Answer 36

Yes

Question 37

What is a reactivity series?

Answer 37

A table listing metals in order of their reactivity with other substances

Question 38

How are metals placed in the reactivity series

Answer 38

It depends on how easily they loose an electron The higher they are in the series the more easy it is for them to lose an electron

Question 39

Where will the metal be which reacts the most easily with water or acids?

Answer 39

At the top as that involves loosing an electron

Question 40

How could you make your own reactive series?

Answer 40

By reacting metals with an acid or water. And putting the metals in order top to bottom of the most-least reactive

Question 41

What is the equasion when a metal reacts with an acid?

Answer 41

Acid + Metal = Salt + Hydrogen (gas)

Question 42

How could you estimate the speed of the reaction between Acids and Metal? What will change is the Metal is more reactive?

Answer 42

The speed of the reaction is indicated by the rate of which the bubbles (of hydrogen) are given off The bubbles will be given off faster The temprature change

Question 43

Give the equasion between a acid and a metal?

Answer 43

Acid + Metal = Salt + Hydrogen

Question 44

Give the equasion between Metal and Water?

Answer 44

Metal + Water = Metal Hydroxide + Hydrogen

Question 45

How are oxides formed? What is this an example of?

Answer 45

Common metals such as iron or aluminium react with oxygen This is an example of oxidation

Question 46

What is oxidation (not in terms of electrons)?

Answer 46

When something gains oxygen

Question 47

What is oxidation (in terms of electrons)?

Answer 47

When something looses electorns OILRIG

Question 48

What is a reduction reaction?

Answer 48

A reaction that seperates metals from oxygen so that you can use the metal

Question 49

What is a reaction that seperates metals from oxygen called?

Answer 49

A reduction reaction

Question 50

What is reduction (not in terms of electrons)?

Answer 50

The loss of oxygen

Question 51

Give the reduction reaction of copper?

Answer 51

2CuO + C = 2Cu + CO^2

Question 52

Give the reaction where magnesium oxidises?

Answer 52

2Mg + O^2 = 2MgO

Question 53

How may some ores be reduced?

Answer 53

By using Carbon as it will bond with the Oxygen

Question 54

Give an example of reduction with Carbon?

Answer 54

Fe^2O^3 + 3C = 4Fe + 3CO^2 Iron(III) oxide + Carbon = Iron + Carbon dioxide

Question 55

What are the 2 ways to extract a metal from it's ore?

Answer 55

Electrolysis Reduction with Carbon

Question 56

What determines if electrolysos will be used of reduction with carbon?

Answer 56

If the metal is higher than carbon in the reactivity series then elecrolysis will need to be used as Carbon won't displace the metal Where else. If carbon is below the metal in the reactivity series then it can be reduced by carbon

Question 57

Why is Gold found in it's element form?

Answer 57

It is so unreactive that it is found by itself

Question 58

Magnesium, Zinc And iron reactions

Answer 58

.

Question 59

How does magnesisum react in a dilute acid?

Answer 59

It reacts vigerously with cold dilute acids and produces a lot of bubbles

Question 60

How does zink react with a dilute acid?

Answer 60

It reacts slowly with dilute acids but more strongly if you heat them up

Question 61

How does iron react with a dilute acid?

Answer 61

It reacts slowly with dilute acids but more strongly if you heat them up