chemical changes

Question 1

please stop calling my amazing cheeky zebra in history class sir gets peeved x

Answer 1

Potassium
Sodium
Calcium
Magnesium
CARBON
Zinc
Iron
HYDROGEN
Copper
Silver
Gold
Platinum

Question 2

What kind of ions do metals form?

Answer 2

PURRSITIVE!

Question 3

How does displacement work?

Answer 3

MORE reactive elements displace LESS reactive elements

Question 4

What kind of ions do acids produce in aqueous solutions?

Answer 4

Hydrogen ions (H+)

Question 5

What kind of ions do alkali produce in aqueous solutions?

Answer 5

Hydroxide ions (OH-)

Question 6

What are strong acids?

Answer 6

An acid that is completely ionised in aqueous solutions

Question 7

What are weak acids?

Answer 7

An acid that is partially ionised in aqueous solutions

Question 8

Give examples of strong acids

Answer 8

-Hydrochloric
-Nitric
-Sulfuric

Question 9

Give examples of weak acids

Answer 9

-Ethanoic
-Carbonic
-Citric

Question 10

How do acids and metals react?

Answer 10

acid + metal → salt + hydrogen

Question 11

How do acids and metal oxides react?

Answer 11

acid + metal oxide → salt + water

Question 12

How do acids and alkalis react?

Answer 12

acid + alkali → salt + water

Question 13

How do acids and metal carbonates react?

Answer 13

acid + metal carbonate → salt + carbon dioxide + water

Question 14

Required practical: making soluble salts

Answer 14

1. Make a saturated solution by stirring copper oxide into sulphuric acid until no
   more will dissolve.
2. Filter the solution to remove excess solid copper oxide.
3. Half fill a beaker with water and heat it over a Bunsen burner. Place an
   evaporating dish on top of the beaker.
4. Add some of the solution to the evaporating basin and heat until crystals begin to
   form.
5. Pour the remaining liquid into a crystallising dish and leave to cool for 24 hours.
6. Remove crystals with a spatula and pat dry between paper towels.

Question 15

How do non metal oxides react with water?

Answer 15

They dissolve to make acidic solutions

Question 16

What is oxidation?

Answer 16

-The loss of electrons
-The gain of oxygen

Question 17

What is reduction?

Answer 17

-The gain of electrons
-The loss of oxygen

Question 18

What is a redox reaction?

Answer 18

When reduction and oxidation occur at the same time

Question 19

What kind of reaction is an acid and a metal?

Answer 19

Redox

Question 20

What is the ionic equation for magnesium reacting with hydrochloric acid?

Answer 20

2H+ (aq) + Mg (s) → Mg2+ (aq) + H2 (g)

Question 21

What are the half equations of magnesuim reacting with hydrochloric acid?

Answer 21

• Mg (s) → Mg2+ (aq) + 2e- (oxidation)
• 2H+ (aq) + 2e- → H2 (g) (reduction)

Question 22

When is electrolysis used?

Answer 22

If the metal is too reactive to be extracted by reduction with carbon or if the metal reacts with carbon

Question 23

Why can electrolytes conduct electricity?

Answer 23

When an ionic compound is molten or dissolved in water the ions are free to move about and conduct electricity

Question 24

What happens when a simple ionic compound is electrolysed?

Answer 24

The metal is produced at the cathode and the non-metal is produced at the anode

Question 25

What happens when an aqueous solution is electrolysed?

Answer 25

Hydrogen is produced at the cathode IF the metal is more reactive than hydrogen. Oxygen is produced at the anode UNLESS the solution contains halide ions in which case the halogen is produced

Question 26

REQUIRED PRACTICAL: TITRATIONS

Answer 26

1.Use the pipette and pipette filler to add 25 cm3 of alkali to a clean conical flask. 2.Add a few drops of indicator and put the conical flask on a white tile. 3.Fill the burette with acid and note the starting volume. 4.Slowly add the acid from the burette to the alkali in the conical flask, swirling to mix. 5.Stop adding the acid when the end-point is reached (the appropriate colour change in the indicator happens). Note the final volume reading.

Question 27

What is the titre?

Answer 27

The difference between the reading at the start and the final reading gives the volume of acid added. This volume is called the titre.