Acids and bases

Question 1

Where does the Ph scale start and end?

Answer 1

0 - 14

Question 2

What number and colour are acidic?

Answer 2

0 - 5
Red

Question 3

What number and colour in neutral?

Answer 3

7
Green

Question 4

What numbers and colour is alkali?

Answer 4

8 - 14
Blue / purple

Question 5

What is an indicator?

Answer 5

And dye that changes colour.

Question 6

What is universal indicator?

Answer 6

• A useful combination of dyes.
• which gives colour to find the PH of a aqueous solution.
• add it to a solution and compare to PH scale.

Question 7

What colours does litmus paper?

Answer 7

Test whether a solution is spaced or alkaline.
- changes colour at PH 7
- red in acidic
- purple in neutral
- blue in alkaline

Question 8

What colours does phenolphthalein go?

Answer 8

-colourless in acidic solution
- bright pink in alkaline solutions.

Question 9

What colours does methyl orange go?

Answer 9

• Red in acidic solutions.
• yellow in alkaline solutions

Question 10

How are acids neutralised?

Answer 10

Adding bases.

Question 11

What ions do acids contain ?

Answer 11

Hydrogen ions (H +)

Question 12

What kind of donors are acids?

Answer 12

Proton donors

Question 13

What ions do alkalines contain?

Answer 13

Hydroxide ions ( OH -)

Question 14

What kind of protons are bases?

Answer 14

Proton acceptors

Question 15

Alkalines are ……. In bases.

Answer 15

Soluble

Question 16

What is the reaction between a acid and a base called?

Answer 16

Neutralisation.

Question 17

What is the equation for neutralisation?

Answer 17

Question 18

What can this reaction also be seen as?

Answer 18

Proton transfer

Question 19

What happens when an acid neutralises a base?

Answer 19

The products become neutral.

Question 20

What is formed during a neutralisation reaction?

Answer 20

A salt

Question 21

What is the general equation for neutralisation?

Answer 21

Acid + base = salt + water

Question 22

What does hydrochloric acid produce?

Answer 22

Chloride salts

Question 23

What does sulphuric acid produce?

Answer 23

Sulphate salts

Question 24

What does nitric acid produce?

Answer 24

Nitrate salts

Question 25

What acid + metal oxide produce?

Answer 25

Salt + water

Question 26

What does acid + metal hydroxide produce?

Answer 26

Salt + water

Question 27

What does acid + ammonia produce?

Answer 27

Ammonium salt

Question 28

When else does salts form?

Answer 28

When acid react with metals or metal carbonate

Question 29

What are titrations used for?

Answer 29

To find out concentrations.
Allow you to find out exactly how much acid is needed to neutralise a quantity of alkali.

Question 30

How do you do do a titration?

Answer 30

1) fill the burette with acid up to near the zero. And record that measurement.
2) pour through a little acid to fill the air gap and discard.
3) measure out 20 ml of alkali using a pipette. And pipette filter. Pour into a conical flask.
4) add 3- 4 drops of phenolphthalein and place under the burette on a white tile.
5) add acid until indicator changes colour, this is called the end point.
6) record amount of acid as your rough titre.
7) repeat until you have concordat results.

Question 31

What are concordat results?

Answer 31

Results within 0.2 ml of each other.
Not including rough titre.

Question 32

What is the equation for calculating titrations?

Answer 32

Moles = concentration x volume
mol mol/dm cubed. dm cubed

Question 33

How do you calculate titrations?

Answer 33

1) find the mean of concordat results.
2) convert cm cubed to dm cubed ( by divide 1000)
3) calculate number of moles of acid added to neutralise the alkali. Using Number of moles = concentration x volume in dm cubed.
4) adjust moles of alkali neutralisation for ratio in question.
5) calculate concentration of the alkali using concentration = number of moles divided by volume