Unit 1 Acids And Bases

Question 1

Indicators

Answer 1

Chemical that change colour at different pH levels

Question 2

What ions are contains in acids

Answer 2

H+ ions

Question 3

What ions are contained in alkalis

Answer 3

OH- ions

Question 4

What ions are contains in neutral

Answer 4

Both H+ and OH- ions

Question 5

What pH is acidic solutions

Answer 5

Less then pH 7

Question 6

What pH is alkaline solutions

Answer 6

Greater than pH 7

Question 7

What solution is this equation for:
[H+]>[OH-]

Answer 7

Acidic solutons

Question 8

How would you word this equation:
[H+]>[OH-]

Answer 8

The concentration of hydrogen ions is greater than the concentration of hydroxide ions

Question 9

What solution is this equation for:
[H+]<[OH-]

Answer 9

Alkaline solutions

Question 10

How would you word this equation:
[H+]<[OH-]

Answer 10

The concentration of hydroxide ions is greater than the concentration of hydrogen ions

Question 11

What is a concentration of H+ and OH- ions and water or a neutral solution?

Answer 11

Number of hydrogen ions = number of hydroxide ions.

Question 12

Do acid and alkali solutions have more H +/OH- ions than pure water?

Answer 12

Acids have more H+ ions than water whereas alkalis have more OH- ions than water

Question 13

Can you explain what is a reversible reaction?

Answer 13

There is a reversible reaction- the reaction goes forward and backwards. The rate of the forward reaction = rate of the back reaction at equilibrium.

Question 14

Which ion is common to all acids?

Answer 14

H+ ions

Question 15

What happens when an acid is diluted?

Answer 15

When diluted with water, the concentration of H+ ions decreases and the pH moves towards 7, but never goes above 7

Question 16

What happens when alkalis are diluted?

Answer 16

When diluted with water, the concentration of OH- ions decreases and the pH moves towards 7 but never goes below 7

Question 17

What are the two stages to forming an acid?

Answer 17

Step 1: a non-metal is burned, forming a non-metal oxide
Step 2: the non-metal oxide dissolves in water

Question 18

What are the two stages of forming an alkali?

Answer 18

Stage 1: a metal is burned, forming a metal oxide
Stage 2: if soluble, the metal oxide dissolves in water to form the metal hydroxide

Question 19

What are metal oxide called if they do not dissolve in water?

Answer 19

They are called bases

Question 20

What is a base?

Answer 20

A substance which reacts with an acid and neutralise it, giving water as the product

Question 21

What happens to metals and nonmetal oxides that do not dissolve in water?

Answer 21

Water will not alter the pH

Question 22

What happens to metals below hydrogen on the ECS

Answer 22

They will not react with acids

Question 23

What is the test for hydrogen?

Answer 23

And lIT splint into a test strip of hydrogen will burn it with a pop

Question 24

When did neutralisation reactions occur?

Answer 24

Neutralisation reactions occur when an acid is neutralised by a base resulting in a neutral solution

Question 25

What is a neutralisation reaction?

Answer 25

It is when hydrogen ions in the acid react with bases resulting in a neutral solution

Question 26

What happens in reactions with metals?

Answer 26

The hydrogen ions from the acids form hydrogen molecules

Question 27

What is the other product formed in a reaction with metals?

Answer 27

The other product formed is a salt

Question 28

When purchasing soluble salt by reacting an acid with a metal, how could you ensure all the acid had reacted?

Answer 28

Add an excess of the metal

Question 29

If you wanted to isolate a solid sample of the soluble salt, what practical technique would you use?

Answer 29

Filteration

Question 30

If you wanted to isolate a solid sample of the soluble salt, what practical technique would you use?

Answer 30

Evaporation

Question 31

How do you make a salts name?

Answer 31

The salt named the pans on the metal and the acid

Question 32

What is the first part of a salt’s name?

Answer 32

The first part comes from the metal (of the base)

Question 33

What is the second part of a salts name?

Answer 33

The second part of a salts name comes from the acid

Question 34

What are the products when an acid reacts for metal?

Answer 34

Products are a salt and hydrogen

Question 35

What does too much acid in a stomach cause?

Answer 35

And indigestion

Question 36

How can a stomach acid be neutralised?

Answer 36

Using indigestion tablets which are alkaline

Question 37

What is produced during a neutralisation?

Answer 37

Water

Question 38

Acid + alkali (metal hydroxide) ->

Answer 38

Salt + water

Question 39

Acid + metal oxide->

Answer 39

Salt+ water

Question 40

Acid + metal carbonate ->

Answer 40

Salt + water + carbon dioxide

Question 41

Why can alkalis be removed by filtrartion

Answer 41

Alkalis tend to be soluble and you cannot revoke by filtration which means that any excess end up in the product salt solution

Question 42

What other salts can be removed during filtering

Answer 42

Excess of insoluble metal carbonate or metal oxides can be removed during filtering

Question 43

Explain why, in the preparation of a given salt, it is often easier to use an insoluble metal carbonate or oxide as the neutraliser.

Answer 43

The insoluble metal carbonate or oxide can be filtered off leaving a pure solution of the salt

Question 44

What is a spectator ion

Answer 44

Spectator ions are ions that remain unchanged by a reaction

Question 45

Acid + metal ->

Answer 45

Salt + hydrogen

Question 46

What is a precipitation reaction

Answer 46

A precipitation reaction is one in which two solutions are mixed an insoluble product (precipitate) is made

Question 47

What is a standard solution

Answer 47

A Standard solution is a solution of accurately known concentration

Question 48

What is titration

Answer 48

An analytical technique that can be used to precisely determine volumes or concentrations for neutralisation reactions.

Question 49

Why is the flask placed on a white tile

Answer 49

The flask was placed on the white tile so that it was easy to see the colour change

Question 50

Why is the rough titration not used to calculate the average

Answer 50

The rough titration is a guide to how much is needed for the end point to be reached

Question 51

The titration should be repeated until two concordant results are obtained. What does the word concordant mean

Answer 51

Concordant titres are within 0.2cm3 of each other. Taking the average of these increases precision

Question 52

How do you prepare a standard solution

Answer 52

Weigh out product and add to beaker. Dissolve in minimum of deionised water and add to standard flask. Rinse beaker with deionised water and add rinsings to flask. Make up to the mark with water. Invert flask.