Acids, Alkalis, Making Salts and Titration

Question 1

What is Acid

Answer 1

-a chemical that gives off hydrogen ions

Question 2

Why is acid considered a proton donor

Answer 2

-because it gives off hydrogen ions

Question 3

Does an acid have to in aqueous solution to be considered a acid

Answer 3

Yes

HCl (aq) is acid
but HCl (g) is not acid

Question 4

What are Strong Acid

Answer 4

When the acid fully break apart when dissolve in water, releasing the hydrogen ion

Question 5

What are Weak Acid

Answer 5

When the acid only break apart some of its hydrogen ion when dissolve in water

Do not completely ionise

Question 6

What can u observe if a strong acid reacts with magnesium

Answer 6

Fizzy/ warm / cloudy

Question 7

What happen if a weak acid react with magnesium

Answer 7

Only a few bubbles

Question 8

What does Ph actually measure

Answer 8

the concentration of hydrogen ion.

The less the concentration of hydrogen, the higher the Ph

Question 9

What Ph is acid

Answer 9

Below Ph7

Question 10

Does strong/weak acid refer to their Ph of the acid

Answer 10

No

Question 11

What is the difference between strong/weak acid in terms of ionisation

Answer 11

-strong means high conc of hydrogen ions produced
-weak means low conc of hydrogen ions produced

Question 12

Explain the rate of reaction of strong compare to the weak acid

Answer 12

Strong acid will have a faster rate of reaction as they have a higher concentration of hydrogen ion since the hydrogen ion are fully break apart in acid

Question 13

What are the similarity of strong acid and weak acid

Answer 13

They both will neutralises the same amount of alkaline

Question 14

metal + hydrochloric acid –> ?

Answer 14

metal chloride + hydrogen

Question 15

What is an indicator

Answer 15

Will determines if something is acid or alkaline by often the change of colour

Question 16

Balance the equation

Mg + HCl–> MgCl2 + H2

Answer 16

Mg + 2HCl–> MgCl2 + H2

Question 17

What is a universal indicator

Answer 17

-a mixture of indicators used to determine how acidic or alkali something is based off of colour

Question 18

What colour is phenolphthalein in acid

Answer 18

Pink

Question 19

What colour is alkaline/neutral in phenolphthalein?

Answer 19

alkali-Pink
neutral-colourless

Question 20

What colour is acid in litmus paper

Answer 20

Red

Question 21

What colour is alkaline in litmus paper

Answer 21

Blue

Question 22

What colour is acid in methyl orange

Answer 22

Red

Question 23

What colour is alkaline in methyl orange

Answer 23

Yellow

Question 24

What colour is neutral in methyl orange

Answer 24

Yellow

Question 25

What colour is acid in Universal indicator

Answer 25

Red-yellow

Question 26

What colour is neutral in Universal indicator

Answer 26

Green

Question 27

What colour is alkaline in Universal indicator

Answer 27

Purple-blue

Question 28

What is a base

Answer 28

Any substance that will neutralise an acid e.g metal oxide Not necessary an alkali

Question 29

What is a alkali

Answer 29

-soluble base with hydroxide ions

Question 30

Are alkali proton donor or acceptor

Answer 30

Proton acceptor

Question 31

What is a salt

Answer 31

-an ionic substance formed when an acid reacts with a base

Question 32

Metal carbonate + acid --> ?

Answer 32

Salt + water +CO2

Question 33

Acid + metal hydroxide --> ?

Answer 33

Salt + water

Question 34

Acid + Ammonia

Answer 34

Ammonium salt

Question 35

Which substance is an ion: ammonia or ammonium

Answer 35

Ammonium is ion NH4+

Question 36

What does Saturated mean

Answer 36

--> The maximum volume of solute that can dissolve in a solvent at certain temperature

Question 37

What is the formula of solubility (g/100g)

Answer 37

Mass of solute /mass of solvent x 100

Question 38

Factor that affect solubility

Answer 38

Temperature, the volume of solvent

Question 39

What is a precipitate

Answer 39

A insoluble product that form after a reaction

Question 40

Are most sulfate (except lead, silver, barium) soluble

Answer 40

Yes

Question 41

Are most chloride (except lead, silver) soluble

Answer 41

Yes

Question 42

Are all nitrate soluble

Answer 42

Yes

Question 43

Are most carbonate soluble

Answer 43

No

Question 44

Are most hydroxide soluble

Answer 44

No

Question 45

Are group 1 metal soluble

Answer 45

Yes

Question 46

Are ammonium compound soluble

Answer 46

Yes

Question 47

Why do we heat to constant mass in the solubility practical

Answer 47

To ensure all the water have been evaporated

Question 48

How to find the solubility of potassium nitrate

Answer 48

-pour in 25cm cubed of warm water into a boiling tube and add potassium nitrate until it become saturated -pour off some solution onto a evaporating basin and record the mass -evaporate the water in basin until constant mass

Question 49

# Magnesium nitrate and Pure dry crystals How to make salt if the salt formed is soluble (6 marker)

Answer 49

Part 1: Made Mg(NO3)2 (4 marking point) ->Heat/warm the acid ->Add magnesium until excess magnesium ->Until saturated/ no reaction occur ->filter the solution into evaporating basin Part 2: Pure Dry Crystals (5 marking point) ->Heat the solution until the point of crystallisation ->Don't heat the solution too much as it will make it anhydraulic ->Leave the solution to cool down so more crystals can form ->Filter crystals ->Dry in warm oven/ windowsill

Question 50

Why was excess magnesium is needed

Answer 50

To ensure that all acid has been neutralise

Question 51

Why will you use the precipitation method

Answer 51

As the salt formed is insoluble

Question 52

# cation and anion Preparing **Insoulble** Salts

Answer 52

Add the equal volume of cation and anion into a beaker Swirl the beaker Pour the solution into a filter paper and filter it Remove the salt and dry it

Question 53

What does it mean by concentration

Answer 53

A measure of how much a substance you have in a give volume Measured in moles per dm^3

Question 54

What's the formular to calculate concentration

Answer 54

Conc (mol/dm^3) = mole /volumes

Question 55

What is titration

Answer 55

Precise way of measuring the concentration of acids and alkali

Question 56

What is a volumetric pipette

Answer 56

A very precise pipette that allow you to accurately measure the volume

Question 57

What is the purpose titration method

Answer 57

To exactly neutralise the alkali or acid, usually Phenolphthalein indicator

Question 58

Why shouldn't you leave the funnel in the top of the burette?

Answer 58

To make sure there isn't additional liquid in the burette

Question 59

How should you measure values on the burette

Answer 59

Measure the value on eye level and read at meniscus

Question 60

Why should you wash both the burette and volumetric pipette

Answer 60

To remove any impurity

Question 61

Why do you need to make sure the space under the tap in the burette is completely filled?

Answer 61

If there is still space under the tap, you will overestimate the result as there is less acid being added to the alkaline than the reading on the burette

Question 62

When should you stop the tap of the burette in titration practical

Answer 62

When the Phenolphthalein indicator turns instantly from pink to colourless