Chapter 11 Acids and Bases - Oxides + Neutralisation

Question 1

What is neutralisation

Answer 1

reaction with between alkali and acid that gives water and salt

Question 2

Where does water come from in neutralisation

Answer 2

The hydrogen ions from the acid and the hydroxide ions from the alkali give water molecules

H+ + OH- —> H2O

Question 3

How does an acid donate protons
How are the protons accepted
what are formed

Answer 3

The H+ ion of an acid is essentially just a proton (no electrons)

This is donated to the Hydroxide ion.

The hydroxide ions accept the proton to form water molecules

Question 4

pH and colour of a neutral substancew

Answer 4

pH: 7
colour: green

Question 5

Real life application of neutralisation

Answer 5

Acidity in soil:

Optimal plant growth requires a soil pH between 5 and 8. Soil pH imbalance to be too acidic reduces plant growth yield. Soil acidity is neutralized by adding lime or powdered limestone.

Question 6

What are oxides

Answer 6

Compounds containing oxygen and another element

Question 7

How are basic oxides formed

Answer 7

In general, metals react with oxygen to form basic oxides

Question 8

What can basic oxides do

Answer 8

They can neutralize acids

Question 9

How are acidic oxides formed

Answer 9

Non-metals react with oxygen to form acidic oxides

Question 10

What happens when the acidic oxides are dissolved in water

Answer 10

they give acids

Question 11

what are amphoteric oxides

define them

Answer 11

amphoteric oxides act as acids and bases.

when presented with an acid they act as a base but when presented with a base they act as an acid

definition: they can NEUTRALISE both acids and alkakis

Question 12

Amphoteric oxide examples

Answer 12

Al2O3
ZnO

Question 13

what are neutral oxides

Answer 13

neutral oxides are neither basic nor acidic

Question 14

examples of neutral oxides

Answer 14

1) Nitrous oxide (N2O)

2) Nitric oxide (NO)

3) Carbon monoxide (CO)

4) Water (H2O)

5) Manganese(IV) oxide (MnO2)

6) Hydrogen peroxide (H2O2)

Question 15

How to prove that an oxide is amphotheric

Answer 15

Show that the oxide reacts with both an acid and a base to give —> salt + water

Question 16

Word and Chem Eqns to prove Al2O3 is amphoteric

Answer 16

with acids:
Aluminium Oxide + Hydrochloric acid —> Alumium Chloride + Water
Al2O3 + 6HCl —> 2AlCl3 + 3H2O

with alkali:
Alumium Oxide + Sodium Hydroxide —> Sodium Aluminate + Water
Al2O3 + 6NaOH —> 2Na2AlO3 + 3H2O

Question 17

Word and Chem Eqns to prove ZnO is amphoteric

Answer 17

with acids:
zinc oxide + hydrochloric acid —> zinc chloride + water
ZnO + 2HCl —> ZnCl2 + H2O

with alkali:
zinc oxide + sodium hydroxide —> sodium zincate + water
ZnO + 2NaOH —> Na2ZnO2 + H2O

Question 18

if a question states how we could show a compound is an acid without using an indicator what to do

Answer 18

add metal
hydrogen is given off/effervescence
burning splint pops

Question 19

what problem arises when a compound of a transition element doesn’t include its oxidation number? eg iron oxide

Answer 19

because they have more than one oxidation state, form ions with different charges.
fe2+ and fe3+

Question 20

what does saturated solution mean

Answer 20

A state of a solution where no more solute can be dissolved in the solution at that given temperature.

Question 21

What kind of oxide is Calcium Oxide

Process to make it

name colours if any

Answer 21

Basic oxide

heat calcium up
plunge it into a gas jar with oxygen

bursts into an INTENSE WHITE FLAME WITH A TINGE OF RED

and leaves white ash which is calcium oxide

Question 22

Chemical reaction for making calcium oxide

Answer 22

2Ca (s) + O2 (g) —-> 2CaO (s)

Question 23

What kind of oxide is Iron (III) oxide

Process to make it

name colours if any

Answer 23

Basic oxide

Heat iron wool
plunge into a jar of oxygen
glows bright and throws out a shower of bright orange sparks

BLACK solid left behind is iron (iii) oxide

Question 24

Chemical equation of making iron (III) oxide

Answer 24

4Fe (s) + 3O2 (g) —-> 2Fe2O3 (s)

Question 25

What kind of oxide is Copper (II) oxide

process to make

Answer 25

basic

Copper ‘turnings’ are heated and then a stream of oxygen passes over it

surface turns BLACK which is Copper (II) oxide

Question 26

Why is the process to make copper (II) oxide different

how are reactivity and oxygen related

Answer 26

Copper too unreactive to catch fire in oxygen

the more reactive the metal is the more vigorously it reacts with oxygen

Question 27

Chemical eqn to make copper (II) oxide

Answer 27

2Cu (s) + O2 (g) —> 2CuO (s)

Question 28

What kind of oxide is carbon dioxide

Process to make it

name colours if any

Answer 28

Acidic oxide

Powdered carbon heated over bunsen burner until RED-HOT

plunged into a jar of o2

glows bright RED and forms CO2 gas

Question 29

Chemical eqn for formation of Carbon Dioxide

Answer 29

C (s) + O2 (g) —> CO2 (g)

Question 30

What kind of oxide is Sulfur Dioxide

Process to make it

name colours if any

Answer 30

Acidic oxide

Sulfur catches fire over a bunsen burner

burns with a BLUE flame

(burns even brighter in pure oxygen)

forms a gas - sulfur dioxide

Question 31

Chemical eqn to form sulfur dioxide

Answer 31

S (s) + O2 (g) —> SO2 (g)