Unit 2: reactivity

Question 1

List properties of metals

Answer 1

Malleable, ductile, conductive (electrical and heat), high density, hard, shiny, solids

Question 2

List properties of non-metals

Answer 2

Dull, poor conductivity, brittle, not ductile, not malleable, low density, solids liquids or gases

Question 3

What happens when metals react with oxygen, and what is this reaction called?

Answer 3

They produce metal oxides, the reactions are oxidation reactions

Question 4

What is an alkali?

Answer 4

An alkali is a base that dissolves in water, it has a pH level greater than 7

Question 5

What is a base?

Answer 5

A base is a substance that can react with an acid and neutralise it

Question 6

What pH level makes a substance acidic?

Answer 6

A pH level of less than 7 makes a substance acidic

Question 7

What pH level makes a substance basic? (alkaline)

Answer 7

A pH level of more than 7 makes a substance basic

Question 8

What pH level makes a substance neutral?

Answer 8

A pH level of 7 (water is neutral)

Question 9

What are the rows and columns called in the periodic table?

Answer 9

The rows are called periods, the columns are called groups

Question 10

What are metal oxides? (pH)

Answer 10

Metal oxides are basic

Question 11

What are non-metal oxides? (pH)

Answer 11

Non-metal oxides are acidic

Question 12

How do metals work with ions?

Answer 12

Elements that react to form positive ions are metals

Question 13

How do metals react?

Answer 13

Metals react by losing their outer electrons

Question 14

What happens when metals lose negative electrons?

Answer 14

They have a positive charge

Question 15

How is the reactivity series determined?

Answer 15

Observing the reactions of metals with water and dilute acids. The more reactive the metal, the more vigorous the reaction.

Question 16

What is the word equation for the reaction of metals with water

Answer 16

Metal (s) + water (l) —– metal hydroxide (aq) + hydrogen (g)

Question 17

What two products are produced when metals react with cold water

Answer 17

A metal hydroxide and hydrogen gas

Question 18

What does aqueous mean? (aq)

Answer 18

Dissolved in water (a solution in which the solvent is water)

Question 19

What will you see in a reaction of metal with water?

Answer 19

Bubble will appear, the metal will get smaller until there is none left

Question 20

What are the metals places in the reactivity series?

Answer 20

Potassium, lithium, sodium, calcium, magnesium, aluminium, zinc, iron, lead, copper, silver, gold

Question 21

What is the word equation for metals reacting with acid?

Answer 21

Acid + metal —– salt + hydrogen

Question 22

What is an exothermic reaction? give an example

Answer 22

An exothermic reaction gives out heat to its surroundings, an metal reacting with an acid is an example of an exothermic reaction.

Question 23

What is an independant variable?

Answer 23

The variable that is changed or altered

Question 24

What is a dependant variable?

Answer 24

The variable that is measured

Question 25

What is a control variable?

Answer 25

A variable that is kept the same

Question 26

What is a displacement reaction?

Answer 26

A displacement reaction is a reaction in which a more reactive metal takes the place of a less reactive metal in a compound.

Question 27

What can we determine from a displacement reaction?

Answer 27

Which of the two metals is less or more reactive

Question 28

What is an oxidation?

Answer 28

An oxidation is a gain of oxygen

Question 29

What is a reduction?

Answer 29

A reduction is a loss of oxygen

Question 30

What is a redox?

Answer 30

A redox is simultaneous oxidation and reduction

Question 31

What is corrosion?

Answer 31

Corrosion is the destruction of materials by chemical reactions with substances in the environment.

Question 32

How do more reactive metals corrode?

Answer 32

Corrosion is generally a slow process, but more reactive metals tend to corrode faster.

Question 33

How do unreactive metals corrode?

Answer 33

Unreactive metals, such as gold and platinum, do not corrode at all

Question 34

What is rusting?

Answer 34

Rusting is a special name given to the corrosion of iron and steel

Question 35

What actually is rust?

Answer 35

Hydrated iron oxide

Question 36

What substances need to be present for rust to form?

Answer 36

Oxygen and water

Question 37

What substance speeds up the rusting of iron?

Answer 37

Salt

Question 38

What is the word equation for rust?

Answer 38

Iron + water + oxygen ----- hydrated iron oxide (rust)

Question 39

What are the three main methods for preventing rust?

Answer 39

Physical barrier, sacrificial protection, alloying

Question 40

What is the physical barrier method?

Answer 40

The physical barrier method creates a barrier between a metal and its environment, using oil, metal, paint etc

Question 41

What is sacrificial protection?

Answer 41

A more reactive metal is placed on the iron that will corrode instead

Question 42

What is alloying?

Answer 42

Iron is combined with other elements to make it more resistant to rust

Question 43

What is universal indicator?

Answer 43

A pH indicator that changes colour depending on the strength of an acid or alkali

Question 44

What are the colours of universal indicator?

Answer 44

≤ 3 Strong acid Red 4–6 Weak acid Orange or Yellow 7 Neutral Green 8–1 Weak alkali Blue ≥ 11 Strong alkali Indigo or Violet

Question 45

What is litmus paper and what colours does it turn?

Answer 45

Purple litmus paper will turn red if the solution is acidic and blue if the solution is basic (alkali)