Chemical Changes Flashcards Preview

Chemistry Paper 1 > Chemical Changes > Flashcards

Flashcards in Chemical Changes Deck (33):
1

What is a base in a reaction.

A base is any substance that reacts with an acid to form a salt and a water.

2

What is an example of a soluble base?

Alkalis

3

Metal reaction with acid:

metal + acid ---> metal salt + hydrogen

4

Metal oxide reaction with acid:

metal oxide + acid ---> metal salt + water

5

Metal hydroxide reaction with acid:

metal hydroxide + acid ---> metal salt + water

6

Metal carbonate reaction with acid:

Metal carbonates + acid ---> metal salt + carbon dioxide + water

7

How are soluble salts made?
Give an example.

By reacting acids with solid insoluble substances.
(e.g. metals, metal oxides, hydroxides and carbonates)

8

How do you make soluble salts?

Add solid to acid until no more dissolves. Filter off excess solid and crystallise to produce solid salts.

9

How do you use titration to produce salts from soluble reactants?

The acid and soluble reactant are mixed in correct proportions and remaining solution is salt and water.

10

How do you crystallise from titration?

Evaporate off remaining liquid by heating and leave to crystallise as the salt cools.

11

Gas test for Hydrogen:

Burning splint test:
- place a lit splint in a tube of hydrogen gas and a pop sound will be heard.

12

Gas test for Carbon Dioxide:

Limewater test:
- Draw a cross on paper, place under flask and the cross will disappear as solid calcium carbonate turns the solution cloudy.

13

What are acids?

hydrogen ions in aqueous solutions
(H+)

14

What are alkalis?

hydroxide ions in aqueous solutions
(OH-)

15

How does an acid and a base neutralise?

Hydrogen ions react with hydroxide ions to produce water.

16

Universal indicator turns...

Red in acid
Green in neutral
Blue in alkali

17

Litmus paper turns...

Red in acid
Purple in neutral
Blue in alkali

18

Methyl Orange turns...

Red in acid
Yellow in neutral
Yellow in alkali

19

Phenolphthalein turns...

Colourless in acid
Colourless in neutral
Pink in alkali

20

What does concentrated mean?

High mass of substance in a given volume of solution.

21

What does dilute mean?

Low mass of substance in a given volume of solution.

22

What is a strong acid?

A strong acid is completely ionised in aqueous solutions.

23

What is a weak acid?

A weak acid is only partially ionised in aqueous solutions.

24

What is hydrogen ion concentration?

As pH decreases by 1 unit (becoming stronger acid), the hydrogen ion concentration increases by a factor of 10.

25

What is electrolysis and how does it work?

The breaking down of a substance using electricity; a current is passed through an electrolyte, causing it to decompose.

26

P
A
N
I
C

P - positive
A - anode
N - negative
I - is
C - cathode

27

O
I
L
R
I
G

O - oxidation
I - is
L - loss
R - reduction
I - is
G - gain

28

What charge do cations produce?

Positive ions.

29

What charge do anions produce?

Negative ions.

30

What do half equations show?

Show how electrons are transferred during reactions, useful for showing the products at each electrode.

31

Why can't an ionic solid be electrolysed?

The ions are in fixed positions so they can't be moved.

32

At the cathode, ..... metal ions reduce to ..... ions.

At the cathode, positive metal ions reduce to metal ions.

33

At the anode, ..... metal ions oxidise to...

At the anode, negative metal ions oxidise to atoms or molecules.