Acids, Bases and Salts Flashcards Preview

Chemistry > Acids, Bases and Salts > Flashcards

Flashcards in Acids, Bases and Salts Deck (48):
1

What colour does acid turn (purple) litmus?

red

2

When do acids exhibit their typical properties?

When dissolved in water

3

What makes acids 'acidic'?

Solutions of acids contain positively charged hydrogen ions

4

What happens to acids when dissolved in water?

In water, the molecules in acids disassociate into ions

5

Describe some of the properties of weak acids

Higher pH (still under 7 though) and low conductivity because when dissolved, only some of the molecules become ions

6

Describe some of the properties of strong acids

Low pH and high conductivity because when dissolved, all of the molecules become ions

7

State the correlation between the concentration of hydrogen ions (in an acidic solution) and the conductivity and pH of that solution.

The higher the concentration of hydrogen ions in an acidic solution, the lower the pH and the higher the conductivity.

8

What is an alkali?

A soluble base

9

What colour do alkalis turn (pink) litmus?

blue

10

What makes alkalis 'alkaline'?

Solutions of alkalis contain negatively charged hydroxide ions.

11

What happens to alkalis when dissolved in water?

The ions in the base seperate

12

Describe some of the properties of strong alkalis.

High pH and high conductivity

13

Describe some of the properties of weak alkalis.

Lower pH (still above 7 though) and low conductivity

14

State the correlation between the concentration of hydroxide ions (in an alkaline solution) and the conductivity and pH of that solution.

The higher the concentration of hydroxide ions in an alkaline solution, the higher the pH and conductivity.

15

pH number of hydrochloric acid

1.0

16

pH number of sulfuric acid

0.7

17

pH number of nitric acid

1.0

18

pH number ethanoic acid

1.0

19

pH number of sodium hydroxide

13.0

20

pH number of potassium hydroxide

13.0

21

pH number of ammonia solution

11.0

22

Colour of methyl orange in acid

red

23

Colour of methyl orange in alkali

yellow

24

Colour of phenolphtalein in acid

colourless

25

Colour of phenolphtalein in alkali

pink

26

What is the pH scale?

A scale which allows you to say how acidic or alkaline a solution is using a scale of numbers from O to 14.

27

Where are the acids on the pH scale?

around 0-6

28

Where are the bases on the pH scale?

around 8-14

29

What method is used to make a salt with an acid and an insoluble metal oxide?

Mix, filter excess, evaporate, crystallisation

30

What is a salt (and what does it consist of)?

A salt is an ionic compound consisting of a negative ion (anion) (non-metal) (formed when an acid dissolves in water and its molecules disassociate into +vely charged hydrogen ions and other -vely charged ion which will form part of the salt) and a positive ion (cation) (metal - EXCEPTION: ammonium is a non-metal, yet, you can make a salt with it and an acid) (formed when the alkali dissolves in water and its molecules disassociate into -vely charged hydroxide ions and other +vely charged ions which will form the other part of the salt)

31

What method is used to make a salt with an acid and an alkali?

Mix, evaporate, crystallisation

32

What is a titration?

A technique used to work out the concentration of an unknown solution when you know the concentration of another solution. In a titration, one reactant is slowly added to the other in the presence of an indicator. The indicator changes colour when the reaction is complete.

33

What method is used to make a salt with an acid and a metal?

Mix, filter excess, evaporate, crystallisation

34

What method is used to make a salt with an acid and an INSOLUBLE base?

Mix + heat, filter excess, evaporate, crystallisation

35

What method is used to make a salt with an acid and an alkali?

Mix, filter excess, evaporate, crystallisation

36

What is a titration?

A technique used to work out the concentration of an unknown solution when you know the concentration of another solution.

37

What method is used to make a salt with an acid and an insoluble carbonate?

Mix, filter excess, evaporate, crystallisation

38

How can the concentration of an acid or alkali be calculated?

By carrying out an experiment called a titration.

39

What is the titre (in a titration)?

The difference between the reading at the start and the final reading gives the volume of acid (or alkali) added, in other words, the titre.

40

How do you calculate the mean of the titre from several repeated same titrations.

You take the two results which are closest to each other and find their mean.

41

What does the concentration of a solution tell us?

How much of a substance is dissolved in a certain volume of solution

42

Convert 1dm3 into cm3.

1dm3 = 1000cm3

43

How do you calculate the molarity of a solution?

n° of moles / volume (dm3)

44

What are anhydrous salts?

Anhydrous salts have no water of crystallisation.

45

What are hydrated salts?

Hydrated salts have water of crystallisation.

46

What happens to hydrated salts when heated?

On heating, hydrated salts give off water vapour and the remaining salt is anhydrous.

47

How are hydrated salts represented in a formula?

n(salt formula) X H2O

48

Name indicators that could be used to show that neutralisation has occurred.

Phenolphthalein turns pink when the neutralisation is complete