Paper 1 past paper questions

Question 1

Describe the structure and bonding in magnesium

Answer 1

There is a giant lattice of cations with electrostatic forces of attraction between cations with delocalised electrons

Question 2

What’s is the formula for reacting magnesium with steam

Answer 2

Mg(s) + H₂O(g) → MgO(s) + H₂(g)

Question 3

What’s are some observations for reacting steam with magnesium

Answer 3

A white flame and a grey powder is formed

Question 4

What’s the least soluble group 2 metal and what is it used for

Answer 4

• Ba(SO₄)
• Barium meals for x rays

Question 5

What is electron impact

Answer 5

The sample being analysed is vaporised and then high energy electrons are fired at it. This usually knocks off one electron from each particle forming a 1+ ion

Question 6

What atoms can be separated with electrolysis

Answer 6

Atoms above carbon in the reactivity series

Question 7

What atoms aren’t separated with electrolysis

Answer 7

Atoms below carbon but above hydrogen in the reactivity series as they can be displaced by carbon instead

Question 8

What are native metals

Answer 8

Metals below hydrogen in the reactivity series and found in their pure metallic form

Question 9

What is the test for reactivity for metals

Answer 9

• Look at the covered in oil
• Observe them in air as some react with oxygen
• observe in cold water as some will react with cold water
• observe in hot water as some will react with hot water

Question 10

Define relative atomic mass

Answer 10

The average mass of an atom compared to 1/12 of a carbon 12 atom

Question 11

What the reason for adding chlorine to drinking water and a disadvantage

Answer 11

Adding chlorine to water kills bacteria but chlorine can be toxic

Question 12

Na+ and F- have the same electron configuration. Explain why a fluoride ion is larger than a sodium ion.

Answer 12

Fluorine has a lower nuclear charge so the attraction to the outer shell of electron is weaker so the atomic radius is larger

Question 13

Why do ionic compounds have high melting points

Answer 13

Because there is a giant ionic lattice with strong electrostatic forces of attraction between the oppositely charged ion so a lot of energy is required to break them

Question 14

how do the results for the flame testa arrise

Answer 14

• electrons are promoted to a higher energy level
• they return to a lower energy shell
• the release energy at different frequency whick we can see as visible light

Question 15

A student plans to titrate botanic acid solution with a solution of ethyl amine explain why this titration couldn’t be done using an indicator

Answer 15

This is a weak acid and weak base titration so the pH change is too gradual

Question 16

Why is Electronspray ionisation is used instead of Elton impact for the ionisation of protein

Answer 16

The protein doesn’t break up

Question 17

How are ions detected in TOF mass spectrometry and how is relative abundance of ions determined

Answer 17

Ions hit the detector where they gain an electron which generates a current
Current is proportional to the abundance

Question 18

State one advantage of using methanol rather than hydrogen in fuel cells in use for cars

Answer 18

Methanol is a liquid so can be easily stored and transported

Question 19

State why fuel cells don’t need to be electrically recharged

Answer 19

There is a continuous supply of reactants

Question 20

What bonds in EDTA form coordinate bonds

Answer 20

4 of the O- ions and 2 N atoms

Question 21

State why the concentration of aluminium sulfate solution can’t be determined by calorimetry

Answer 21

Colourless solution/ cant absorb visible light

Question 22

Why is the enthalpy of hydration of fluoride ions more negative than the enthalpy of hydration of chlorine ions

Answer 22

Fluoride ions have a higher charge density because the ion is smaller
Stronger attraction to the electron

Question 23

what would happen to the EMF if the surface area of the platinum electrode increases

Answer 23

The EMF won’t change

Question 24

what is the equation for sulfur and water

Answer 24

SO₂ +H₂O → H₂SOH₄

Question 25

reaction between phosphorus and excess oxygen

Answer 25

P₄ +SO₄ → P₄O₁₀

Question 26

2 features of a reaction in a dynamic reaction

Answer 26

* forward and reverse reactions proceed at the same rate * concentration of products and reactions are the same

Question 27

Why is this the enthalpy of hydration for Ca2+ less exothermic that the value for Mg2+

Answer 27

Ca2+ has a lower charge to size ratio that Mg2+ Weak attraction to water

Question 28

Explain in terms of crystal structure why silicon(IV) oxide has a higher melting point that phosphorus(V) oxide

Answer 28

Silicon oxide is a giant covalent structure Strong covalent bonds need a lot of energy to overcome Phosphorus oxide is a simple covalent structure with weak van der waals forces

Question 29

Give the formula of a hydroxide of an element in period 3 used in medicine

Answer 29

Mg(OH)2

Question 30

Why does [H2O] no show up in Kw expressions

Answer 30

H2O is constant

Question 31

Why is water neutral at 50 degrees

Answer 31

Dissociation of each water molecule gives one H+ ion and OH- ions [H+] = [OH-]

Question 32

Why is the entropy for carbon dioxide greater than that for carbon

Answer 32

CO2 is a gas and more disordered

Question 33

Suggest why two cobalt(III) complex ions have different electrode potentials

Answer 33

They have different ligands

Question 34

Why would the emf value differ between the same half cells

Answer 34

It’s calculated under non standard conditions

Question 35

why do isotopes have the same chemical properties

Answer 35

because the have the same electronic configuration

Question 36

why is an indicator not added to a titration involving KMO₄

Answer 36

KMOO₄ is self indicating

Question 37

what is the defentition of mean bond enthalpy

Answer 37

it the energy change required to break 1 mole of gaseuos bonds

Question 38

how can a buffer solution be made from solutions of potassium hydroxide and ehtanoic acid

Answer 38

add enough KOH to the enthanoic acid so the acid is partially neutralised KOH + CH₃COOH → CH₃COOK + H₂O CH₃COO- can react with any added acid (H+ ions)

Question 39

exaplain why solutions contain [CuCl₄]2- ions are yellow

Answer 39

white light is absorbed only yellow light is transmitted

Question 40

whats the function of a porus separator

Answer 40

act as a salt bridge

Question 41

why are the EMF valuves if the acidic and alkaline oxygen fuel cekks are the same

Answer 41

they have the same overall reaction

Question 42

Suggest why sodium oxide forms alkaline solutions when it reacts with water

Answer 42

Sodium oxide contains O2- ions which react with water to form OH- ions

Question 43

Suggest why a reaction would have an enthalpy change of 0

Answer 43

Same number of broods broken as formed that have similar values for enthalpy

Question 44

the pH of magnesium hydroxide compared to calcium hydroxide

Answer 44

magnesium hydroxide would be more acidic becasue magnesium hydroide is less soluable

Question 45

the crystal structure of silicon dioxide and sulphur trioxide

Answer 45

giant covalent structure simple molecule (macromolecule)

Question 46

explain why silicon dioxide has a higher melting point than sulphur trioxide

Answer 46

there's covalent bonds in silicon dioxide and there's van der Waals forces in sulphur trioxide and covalent bonds are stronger than van der Waals forces so more energy is required to overcome them

Question 47

reaction for sulphur trioxide and potassium hydroxide

Answer 47

SO₃ + OH- → HSO₄-

Question 48

excess magnesium oxide and phosphoric acid

Answer 48

3MgO + 2H₃PO₄ → Mg₃(PO₄)₂ + 3H₂O

Question 49

explain why colorimetry cant be used to determine the concentration of certain solution

Answer 49

the central metal ion has a full 3d subshell so it would be colourless

Question 50

test to distinguish between MgCl₂ and AlCl₃

Answer 50

reagent: NaOH or a group 1 hydroxide observation with MgCl₂: white ppt observation with AlCl₃: white ppt which dissolves in excess NaOH or reagent: group 1 carbonate observation with MgCl₂: white ppt observation with AlCl₃: white ppt and effervescence

Question 51

definition of enthalpy change

Answer 51

the heat change at constant pressure

Question 52

definition for enthalpy of hydration

Answer 52

the enthalpy change when one mole of gaseous ions is dissolved in water to give one mole of aqueous ions

Question 53

what affects the enthalpy of hydration value

Answer 53

at atom with a higher charge size ratio would have a weaker attraction to the delta negative O in water

Question 54

why do Zn2+ ions don't catalyse reactions

Answer 54

because the don't have a variable oxidation state

Question 55

Rank these in terms of most exothermic enthalpies of lattice formation - MgCl2 - MgO - BaCl2

Answer 55

- MgO would be the most ectothermic because O had a smaller atomic radius that Cl - MgCl2 because Mg has a smaller atomic radius than Ba - BaCl2

Question 56

What does each halogen reduce concentrated sulphuric acid to

Answer 56

- Fluorine (F₂) and Chlorine (Cl₂) These are weak reducing agents. No redox reaction occurs with concentrated sulfuric acid. H₂SO₄ may act as an acid (proton donor), but it is not reduced. - Bromide ions (Br⁻) are stronger reducing agents. Br⁻ reduces H₂SO₄ to: Sulfur dioxide (SO₂) - Iodide ions (I⁻) are very strong reducing agents. I⁻ reduces H₂SO₄ to multiple products depending on conditions: Sulfur dioxide (SO₂) Sulfur (S) Hydrogen sulfide (H₂S)