chemistry topic 4

Question 1

what is an ore

Answer 1

A metal compound within a rock is an ore.

Question 2

what must happen for metals to be extracted from their oxides

Answer 2

To extract metals from their oxides, the metal oxides must be reduced (have oxygen removed).

Question 3

what happens to metal atoms when the metal reacts with other substances

Answer 3

When metals react with other substances the metal atoms form positive ions.

Question 4

what is the reactivity of metals linked to

Answer 4

its tendency to form positive ions

Question 5

how must metals above carbons level of reactivity be extracted

Answer 5

by electrolysis.

Question 6

how must metals below carbons level of reactivity be extracted

Answer 6

Metals below carbon can be extracted from their ores by reduction using carbon.
(reduction involves the loss of oxygen.)

Question 7

what can a more reactive metal do to a less reactive metal

Answer 7

A more reactive metal can displace a less reactive metal
from its compound in displacement reactions.

Question 8

what is oxidisation

Answer 8

Oxidation Is Loss of electrons

Question 9

what is reduction

Answer 9

Reduction Is Gain of electrons

Question 10

what is the equation for when a metal reacts with an acid

Answer 10

Metal + acid -> salt + hydrogen

Question 11

complete the equation Magnesium + hydrochloric acid

Answer 11

Magnesium + hydrochloric acid –> magnesium chloride + hydrogen

Question 12

what is the name of the salt formed when a metal reacts with Hydrochloric acid

Answer 12

Chloride

Question 13

what is the name of the salt formed when a metal reacts with Sulfuric acid

Answer 13

Sulfate

Question 14

what is the name of the salt formed when a metal reacts with Nitric acid

Answer 14

Nitrate

Question 15

what happens in a reaction between magnesium and hydrochloric acid

Answer 15

the hydrogen ions
are displaced from the solution by magnesium as the magnesium is more reactive than hydrogen.

Question 16

what are ions that dont change a reaction known as

Answer 16

spectator ions.

Question 17

what is the equation for Making Soluble Salts from acids and alkalis

Answer 17

Acid + Alkali (or base) → Salt + Water

Question 18

what is the equation for Making Soluble Salts from acids and metal carbonates

Answer 18

Acid + Metal carbonate → Salt + Water + Carbon dioxide

Question 19

describe the practical for making crystals

Answer 19

1. Add acid to a beaker
2. Warm acid using bunsen burner
3. Add [metal] oxide
4. Stir
5. Continue adding until [metal] oxide is in excess - you will see
   undissolved powder at the bottom of the beaker (this ensure that all the acid
   has fully reacted)
6. Filter using a filter paper and funnel - to remove excess [metal] oxide
7. Heat solution in an evaporating basin - removes
   excess water
8. Leave to crystallise

Question 20

what do Acids contain

Answer 20

hydrogen ions (H+)

Question 21

what do Alkalis contain

Answer 21

hydroxide ions (OH–)

Question 22

describe the titration practical

Answer 22

1. Measure volume of acid using
   measuring cylinder
2. Pour acid in conical flask
3. Add indicator to flask
4. Sodium hydroxide in burette
5. White tile under flask - makes it easier to see colour change
6. Add sodium hydroxide slowly and swirl flask
7. Colour change - pink to colourless for phenolphthalein indicator
8. Check volume of sodium hydroxide added

Question 23

what must happen to acids when they are mixed with water for them to be acidic

Answer 23

Acids must dissolve in water to be acidic

Question 24

what is a concentrated acid

Answer 24

A concentrated acid has a small amount of solute dissolved in the solvent.

Question 25

what is a dilute acid

Answer 25

A dilute acid has a larger amount of solute dissolved in the solvent

Question 26

what happens when an ionic compound is melted or dissolved in water

Answer 26

the ions are free to move about the liquid or solution.

Question 27

what happens to positive ions during electrolysis

Answer 27

Positive ions (cations) go to negative electrode (cathode) and are reduced

Question 28

what happens to negative ions during electrolysis

Answer 28

Negative ions (anions) go to the
positive electrode (anode) and are oxidised.

Question 29

describe the electrolysis required practical

Answer 29

1. Pour ionic solution into beaker [sodium chloride]
2. Put 2 graphite electrodes into beaker - graphite is unreactive
3. Switch on power supply
4. Bubbles of chlorine gas produced at the anode
5. Bubbles of hydrogen gas produced at cathode
6. Sodium hydroxide left in beaker