Paper 1- 2023

Question 1

PF3 shape

Answer 1

Trigonal pyramidal or tetrahedral
1Lp

Question 2

Why ox staye of chromium is zero for Cr(PF3)6?

Answer 2

PF3 is neutral/has no charge and complex is neutral/no charge

Question 3

Bonding between N and H on ammonia?

Answer 3

Covalent

Question 4

Formation of one complex with Cr in 3+ ox state?
CrCl3+ 5H2O

Answer 4

[Cr(H2O)5Cl]Cl2

Question 5

EMF affected by SA increasing

Answer 5

Had no effect

Question 6

E0 for MgCl2 and Water equation when cell operating

Answer 6

Mg+2HCl—>MgCl2 +H2
Mg+ 2H+ —>Mg2+ +H2

Question 7

Displayed formala for anion when SO3 reacts with water

Answer 7

Remove H on OHs and have negative ion

Question 8

Magnesium add steam and observation

Answer 8

Mg+H2O—>MgO+H2
White solids/white flame

Question 9

Partial pressure

Answer 9

Times MF by Kpa(pp)

Question 10

Kp

Answer 10

Products divided by reactants

Question 11

Mixture compressed into smaller volume affect on yield of O2 and Kp

Answer 11

Decreases yield
No effect on Kp

Question 12

Molar enthalpy change when CaCl2 dissolves in water

Answer 12

Arrows point up like formation

Question 13

Affect on temp when CaCl2 dissolves in water

Answer 13

Temp increases

Question 14

Why 2nd ionisation of Ca greater than 1st

Answer 14

Requires more energy to remove a +ve ion

Question 15

How to form a solution

Answer 15

-Transfer solution to volumetric flask
-Add washing’s using distilled water and make up to 250cm3
-Invert flaps to mix

Question 16

Why is pipette rinsed with small vol of hydroxide solution

Answer 16

So titration done with known conc of OH
Avoid contamination

Question 17

Why remove funnel from burette before titration?

Answer 17

Drops of acid could fall into burette
Decreases titre

Question 18

Total percentage uncertainty

Answer 18

Uncertainty/volume X100

Question 19

Why solution with complex is acidic

Answer 19

AL3+ has greater charge density greater polarising power
Weakens O H bond more acidic

Question 20

+ve electrode half equation when oxygen reacts with hydrogen to form water

Answer 20

O2+4H++4e- —>2H2O

Question 21

Negative electrode half equation when methanol react with water to produce H+ and CO2?

Answer 21

CH3OH +H2O—>CO2+ 6H+6e-

Question 22

Why fuel cells don’t need to be electrically charged

Answer 22

Fuel/ reactants continuously supplied

Question 23

Advantage of using methanol rather than H2 in fuel cells for cars

Answer 23

Methanol can be transported and stored easily

Question 24

Electron impact vs electrospray

Answer 24

Impact loses e-
Spray loses H+

Question 25

Time if flight to find mass no.

Answer 25

Once mass is found find mass of one ion(\1000) Multiply by avogadros constant

Question 26

Tof calculations

Answer 26

Once mass is found find mass of one ion(\1000) Multiply by avogadros constant

Question 27

How Ions are detected and abundance

Answer 27

Detected as each ion gain electron Current proportional to abundance

Question 28

Electro spray used instead of impact for ionisation of protein

Answer 28

Protein doesn’t break up or fragment

Question 29

Why can’t you use indicator for WA WB titration

Answer 29

WA WB titration. Ph change is too gradual colour change is difficult to judge