C3 Structure And Bonding

Question 1

How does graphite conduct electricity

Answer 1

Delocalised electrons are free to move through graphite so can carry charges and allow an electrical current to flow

Question 2

Nanotube

Answer 2

Hollow cylinder of carbon atoms

Question 3

Relative mass proton neutron electron

Answer 3

Proton = 1

Neutron = 1

Electron = 0

Question 4

Ion

Answer 4

When number of protons is different to number of electrons

Question 5

Isotope

Answer 5

Atom of same element with same number of protons but different number of neutrons

Question 6

Why do solid ionic substances not conduct electricity

Answer 6

Ions are fixed in position and not free to carry charge

Question 7

Delocalised

Answer 7

Free to move through the whole structure

Question 8

How are positive metal ions attracted to delocalised electrons

Answer 8

Electrostatic force of attraction

Question 9

How are pure metals malleable

Answer 9

Layers can slide over each other

Question 10

4 properties of pure metals

Answer 10

Malleable

High melting boiling points

Good conductors of thermal energy

Question 11

What did James Chadwick discover

Answer 11

Neutrons

Question 12

2 properties of nanotubes

Answer 12

High tensile strength

Conduct electricity

Question 13

How nanoparticles are able to catalyse reactions

Answer 13

The large surface area to volume ratios of nanoparticulate substances allows them to act as catalysts

Question 14

How a metal and nanoparticles of the same metal can have different properties

Answer 14

The tiny size of nanoparticles compared to the same material in bulk

Question 15

Why pure water can’t conduct electricity

Answer 15

Does not contain ions

Question 16

Describe how metals conduct electricity

Answer 16

Due to the metallic bonding

In metallic bonding, the outer electrons are delocalised (free to move)

This produces an electrostatic force of attraction between the positively charged metal ions, and the negatively charged delocalised electrons

Question 17

What happens when a magnesium atom reacts with an oxygen atom

Answer 17

The magnesium atom loses two electrons to form the Mg2+ cation

The oxygen atom gains these electrons to form the O2– anion

Question 18

Describe the structure and bonding of diamond

Answer 18

Each carbon atom is joined to four other carbon atoms by strong covalent bonds

Giant covalent structure

Question 19

The student adds zinc oxide to hydrochloric acid until the zinc oxide is in excess

Give one observation that the student could make to show that the zinc oxide is in excess

Answer 19

Undissolved zinc oxide at the bottom of the reaction container

Question 20

Why is excess zinc oxide used rather than excess hydrochloric acid?

Answer 20

Zinc oxide is insoluble in water, while hydrochloric acid is soluble

Question 21

One other compound that the student could add to hydrochloric acid to produce zinc chloride

Answer 21

Zinc sulfate

Question 22

Explain how these fractions are obtained from crude oil by fractional distillation

Answer 22

Crude oil is separated by fractional distillation

Crude oil is heated to vaporize the different hydrocarbons in a tank which is cool at the top and hot at the bottom

The vapours then rise and the different hydrocarbons condense at their boiling points

Question 23

Petrol contains a hydrocarbon with the formula C9H20

Complete the equation for the complete combustion of C9H20

Answer 23

C9H20 + 14O2 → 9CO2 + 10H2O

Question 24

Conditions for cracking

Answer 24

High temperatures typically between 450 C to 750 C

Question 25

How many outer electrons do noble gases have

Answer 25

8

Except helium has 2

Question 26

2 C(s) + SiO2(s) → Si(s) + 2 CO(g)
Explain what this reaction shows about the position of silicon in the reactivity series

Answer 26

Carbon is more reactive than silicon

Question 27

Reactivity series

Answer 27

lists the metals in order of reactivity

From the most reactive at the top potassium to the least reactive at the bottom gold

Question 28

Top 3 of reactivity series

Answer 28

Potassium

Sodium

Lithium

Question 29

3 last in reactivity series

Answer 29

Silver

Gold

platinum (lowest)

Question 30

Why aluminium is more expensive than carbon.

Answer 30

Large amounts of electrical energy used in the extraction process for aluminum

Question 31

1 observation the student can make to show the zinc oxide is in excess

Answer 31

Solid no longer disappears

Solid remaining

Question 32

How the student obtains crystals of zinc chloride from a solution of zinc chloride

Answer 32

Heat until crystallisation point is reached

Leave solution to cool

Question 33

How zinc copper and another substance can be used to light a lamp

Answer 33

Solution in container

Zinc, electrode and copper electrode both inserted into solution

Question 34

Why rubidium is more reactive than potassium

Answer 34

Rubidium’s outer electron further from nucleus

Less electrostatic attraction between nucleus and outer electron

Outer electron more easily lost

Question 35

Equation for reaction of rubidium with water

Answer 35

Rb + 2H2O ————-> 2RbOH + H2

Question 36

Metal react with water

Answer 36

Metal + water ———-> metal hydroxide OH- + hydrogen H2

Question 37

Noble gases boiling point trend

Answer 37

Increase as go down the group

Question 38

How alkaline solution is produced

Answer 38

Sodium ions and hydroxide ions are left in solution

Hydrogen ions reduced

Chloride ions oxidised

Question 39

Why products are difficult to separate if magnesium used to reduce silicon dioxide

Answer 39

Both products are solid

Question 40

Calculate the minimum mass in grams of magnesium needed to completely reduce
1.2 kg of silicon dioxide.

Answer 40

40 x 24 = 960 grams