Paper 1-2022

Question 1

Two features of dynamic equilibrium

Answer 1

Conc remains constant
Foreward and backwards reaction occur at the same/equal rates

Question 2

Relative atomic mass

Answer 2

Average mass of one atom of an element relative to 1/12th mass of one atom of carbon 12

Question 3

Relative abundance

Answer 3

Decide by total relative abundance not by 100

Question 4

How is relative determined in TOF spec

Answer 4

When ions hit detector the gain electrons
Abundance depends on the size of the current

Question 5

Ionic equation of KMNO4- and acidified H2O2

Answer 5

2MnO4- +6H+ +5H2O2—> 2Mn2+ +8H2O +5O2

Question 6

Why indicator not added to titration

Answer 6

KMNO4- is self indication/ no longer decolourises at end point

Question 7

Cm3 to m3

Answer 7

Divide by 1,000,000

Question 8

Kpa to pa

Answer 8

X1000

Question 9

Mean bond enthalpy definition

Answer 9

Av. heat energy required to break 1 mol bond averaged over range of compounds/ molecules

Question 10

How is buffer solution made

Answer 10

Add excess acid to hydroxide OR add enough hydroxide to acid so acid is partially neutralised

Question 12

Ph of BaPH is lower at 50° than 10°. Deduce why exactly 22.45cm3 of HCL that should be added to neutralise another 25cm3 of BaOH at 10°

Answer 12

Same conc. of OH

Question 13

Reaction between KOH and ethanoic acid

Answer 13

CH3COOH+KOH—> CH3COO-K+ +H2O

Question 14

How this does buffer solution resist Ph change when small amount of acid added

Answer 14

CH3COO- reacts with the H+

Question 15

False statement about MgOH2

Answer 15

Doesn’t form solution with PH=14 at 25°

Question 16

Al2O3 reaction with H2SO4

Answer 16

Al2O3+ 3 H2SO4–> Al2(SO4)3 +3H2O

Question 17

Identify a way to distinguish between SO2 and SO3 with same conc

Answer 17

PH meter
SO2- Ph:2-3
SO3- ph:0-1

Question 18

Mass spec of phosphorus has peak at mz 124. Formula of species responsible for peak

Answer 18

31P4+ /P4+

Question 19

Phosphorus oxide and Sodium hydroxide

Answer 19

P4O10 +12NaPH—> 4Na3PO4 +6H2O

Question 20

Why is reaction of chlorine with water redox reaction?

Answer 20

Cl2 gains electrons to form Cl- and loses electrons to form CLO-

Question 21

Observation when bubbling cl2 gas through Sol. of NaI and ionic equation

Answer 21

Brown solution or black solid forms
Cl2+2I- —> 2Cl- +I2

Question 22

Few drops of conc H2SO4 added to NaI and two gaseous sulfur containing products formed. Give equation and role of H2SO4

Answer 22

H2SO4+ 2H+ +2I- —>SO2+2H2O+I2
H2SO4 8H+ +8I- —> H2S +4H2O +4I2
Ox. Agent

Question 23

Acidified AgNO3 added to unknown impure sodium Halode and observed bubbles of gas and colourless sol. Student bubbles gas through CaOH2 and white ppt forms. Identify halode, gas and ionic eq of gas from impurity.

Answer 23

NaF
Co2
CO32- +2H+ —> CO2 +H2O

Question 24

How to figure out shape of molecule
Ie. ClF2+

Answer 24

Central atom number of electrons- Cl=7e
Bonding pairs- F=2
9e- -1= 8e-
Therefore 2bp and 2lp

Question 25

Explain any aq sol ofntainibf some ions are Yellow

Answer 25

Visible/white light absorbed exciting d electrons and only yellow light was transmitted/reflected

Question 26

Three ways transition metal complex can be cha fed to alter colour

Answer 26

Variable oxidation state Different ligands Different coordination number

Question 27

Shape of [CuCl4]2-

Answer 27

Tetrahedral

Question 28

Function of proud separator

Answer 28

Allows free flow of ipms

Question 29

Half equations for alkaline hydrogen fuel cell

Answer 29

2H2O +2e- —> 2OH- +H2

Question 30

Why EMf bailed for acidic and alkaline hydrogen fuel cells are the same

Answer 30

Same overall reaction