Acids, Alkalis And Salts

Question 0

Litmus paper

Answer 0

Not used- this turns red and blue in the presence of acid/alkali

Question 1

How to recognise a carboxylic acid

Answer 1

O
| |
C - OH

Question 2

Universal indicator

Answer 2

This is used- turns any colour of pH scale when aded to an acid or alkali

Question 3

What do all acids contain

Answer 3

Hydrogen

Question 4

pH of acids

Answer 4

6 or less

Question 5

pH of alkali

Answer 5

8 to 14

Question 6

What is the neutral pH and what colour is it

Answer 6

7 and murky green

Question 7

Colour of an acid

Answer 7

Yellow to very dark brick red

Question 8

Colour of an alkali

Answer 8

Dark green to very dark navy/black

Question 9

What does the pH scale do

Answer 9

Measures the amount of hydrogena in a solution

Question 10

Do alkalis or acids have more hydrogens

Answer 10

Acids

Question 11

What is an indicator

Answer 11

Substance which changes colour when reacted with an alkali or an acid

Question 12

Sodium hydroxide and water

Answer 12

Releases a hydrogen ion because it is acid

Question 13

Hydrogen chloride in water

Answer 13

HCl –> H^+ and Cl^-

H2O

Question 14

What are acids

Answer 14

Acids are substances which form hydrogen atoms when added to water

Question 15

Sulphuric acid and hydrochloric acid

Answer 15

Sulphuric acid is more acidic because make hydrogen atoms are released (2 opposed to 1)

Question 16

Reversible reactions and acids

Answer 16

If the reaction is reversible, the acid won’t be very strong because the hydrogens are constantly being taken back in after being released

Question 17

Partial dissociation

Answer 17

Not all hydrogens are realised- weak acid

Question 18

Complete dissociation

Answer 18

All hydrogens are released- strong acid

Question 19

Electrolyte

Answer 19

Substance which when dissolved in water allows electricity to flow through it

Question 20

Salt is

Answer 20

A metal compound

Question 21

What do bases and indicators do

Answer 21

Neutralise acids and form salts

Question 22

All reactions to make a salt

Answer 22

Acid+metal –> salt+hydrogen
Acid+metal oxide –> salt+water
Acid + metal hydroxide (alkali) –> salt+water
Acid +carbonate –> salt+ water+ carbon dioxide

Question 23

Acid and metal

Answer 23

Zinc and sulphuric acid
Mix and turns cloudy, zinc gives of bubbles, breaks down and turns red
Forms zinc sulphate

Question 24

Acid + metal oxide

Answer 24

Heat sulphuric acid Add carbon oxide until it doesn't dissolve Filter to blue liquid Heat until you're left with blue salt

Question 25

Alkali and an metal hydroxide

Answer 25

Hydrochloric acid+UI and sodium hydroxide+ UI Mix until green Add carbon to take out colour Filter and then heat until water evaporates and salt is left

Question 26

Hydrochloric acid -->

Answer 26

Chloride HCl

Question 27

Sulphuric acid -->

Answer 27

Sulphate H2SO4

Question 28

Nitric acid -->

Answer 28

Nitrate NO3

Question 29

Metals always ____ electrons

Answer 29

Lose (positive)

Question 30

Non metals always ____ electrons

Answer 30

Gain (negative)

Question 31

3 common acids

Answer 31

Hydrochloric HCl Sulphuric H2SO4 Nitric HNO3

Question 32

4 common alkalis

Answer 32

Sodium hydroxide NaOH Potassium hydroxide KOH Magnesium hydroxide Mg(OH)2 Calcium hydroxide Ca(OH)2

Question 33

Solubility rules

Answer 33

Sodium, potassium, ammonium salts and carbonates All nitrates Common chlorides (not silver or lead) Common sulphates (not barium calcium or lead)

Question 34

Preparation of insoluble salts

Answer 34

``` Precipitation reactions Mix two aqueous solutions One must have positive ion and other must have negative ion AgNO3 + NaCl --> AgCl + NaNO3 Ag^+ + Cl^- --> AgCl ```

Question 35

Common salt from hydrochloric acid

Answer 35

Sodium chloride

Question 36

Common salt from nitric acid

Answer 36

Magnesium nitrate

Question 37

Common salt from sulphuric acid

Answer 37

Ammonium sulfate

Question 38

What metals react with dilute acids

Answer 38

Metals above hydrogen in the reactivity series (magnesium, zinc, iron and aluminium)

Question 39

Acids used in dilute form to make a salt

Answer 39

Only sulphuric acid and hydrochloric acid, nitric acid reacts in a strange way so isn't used

Question 40

What experiments are there for dilute acids

Answer 40

Dilute acid + metal Dilute acid + base Dilute acid + metal carbonate

Question 41

Dilute acid + metal forms

Answer 41

A salt

Question 42

Dilute acid + base forms

Answer 42

A salt and water

Question 43

Dilute acid + metal carbonate

Answer 43

A salt, water and carbon dioxide

Question 44

What is titration

Answer 44

Method of finding out the volume of one solution that is required to react with a given volume of another solution- normally used to find out the volume of acid required to react with a given volume of an alkali

Question 45

What is an end point and what can it be shown by?

Answer 45

End point is when the maximum amount of ions have reacted- there may still be hydroxides or hydrogens left in the substances if they are of different concentrations Phenolphthalein changes colour at end point

Question 46

Method of acid-alkali titration

Answer 46

- Use a pipette to measure 25.0cm3 of alkali - Put this in a conical flask - Add a few drops of methyl orange - Put acid in a burette and note down the initial reading - Add acid gradually to the conical flask until a colour change is visible - Note final reading of burette - Subtract initial from final - This is the amount of acid needed to neutralise 25cm3 of the alkali

Question 47

Neutralisation/end point?

Answer 47

End point isn't always neutralisation because if the substances are different concentrations there may still be unreacted ions left

Question 48

Equation to find concentration of a substance

Answer 48

Concentration(mol/dm3)= moles/volume(dm3)

Question 49

1dm3 =

Answer 49

1000cm3