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AQA Chemistry New AS Unofficial Mark Scheme

If you know anymore questions or answers please reply and the number of marks.
What is the full electronic configuration of Al? 1s2,2s2,2p6,3s2,3p1

What is the full electronic configuration for Cr+3? 1s2,2s2,2p6,3s2,3p6,3d3

What is the formula of the ion with same electronic configuration of Krypton?
Sr2+ (strontium)

What compound has a +2 and -3 ions and has the same number electrons as Argon?
Ca3P2

Which ion has a smaller atomic radius Mg2+ or Na+?
Mg 2+
because has the same number of electrons, same shielding but more protons. So greater nuclear charge and attraction for outer electrons.

What is the first ionisation energy of Na?
Na (g) --> Na+ (g) + e-
Diagram-Mark where the Mg or was it Si?
Was and then mark the point where Sulphur was on the First ionisation graph.
Mg/Si should have been above so the line was increasing.
Sulphur should have been below Phosphorus but above Silicon.

Why does Sulphur have a different first ionisation energy compared to Phosphorus?
-Both have same shielding and in the same orbital the 3p orbital
-Sulphur is paired with an electron in the 3p orbital whilst Phosphorus isn’t
-There’s repulsion between the negatively charged electrons
-So electrons are easier to remove

What is the method of making a standardised solution of 250cm^3? (6 marks)
-Weigh out known mass on weighing boat using a mass scale
-Remember to deduct the mass of the weighing boat to find the exact mass of the solid. (or zero the scale mass)
EDIT: You may not need this part as you've been told the known mass
-Then transfer the contents into a beaker. Use distilled water to make sure all solids are in the beaker.
-Then add bit more distilled water
-Stir with a glass rod to make sure it's all mixed
-Then pour solution into a Volumetric flask using a funnel
-Clean the funnel with distilled water
-Then fill the volumetric flask to the 250cm^3 mark. At near the mark use a pipette to add water dropwise and until meniscus is on the mark line.
Then place stopper on it. Twist the volumetric flask a few times to ensure it's all mixed.

Find mean titre value.
Ignore the first number as it was the rough one when calculating mean.
EDIT: You were only supposed to use 2 values that are 0.1 part when calculating mean.

What was the concentration of the solution.

Student titrated, what should she to improve her methods so there's a smaller percentage uncertainty?
-Titrate a greater volume of solution
-Why? So there's a greater value as percentage uncertainty= uncertainty/value *100. Bigger volume means there's a greater titre value.

Why does Bromine have lower boiling point than Magnesium?
-Bromine has a simple molecular structure.
-There’s weak Van der Waals forces between molecules.
-So smaller amount of energy needed to break these forces.
-Magnesium has a metallic lattice.
-It has many strong metallic bonds.
-Bonds formed from the strong attraction between positiveions and delocalised electrons.
-The metallic bonds are stronger than the Van der Waals forces

How do the ions get accelerated, detected by ToF and how abundanceis measured?
- Accelerated by negative electric field
-The ions reach the detector and generate a small current, which is fed to a computer for analysis. The current is produced by electrons transferring from the detector to the positive ions. The size of the current is proportional to the abundance of the species.

Calculation to find mass of one ion.
1/Avogadro constant * mass. Then divide by 1000 to put it in Kg.
Using kinetic energy, find velocity.
Starts with 1........ Quite a large number.

Draw the spectrum of Br2 with two isotopes of equal abundance.
Screen Shot 2016-05-27 at 15.12.40.png

What's the Mr of the isotope?
Maybe 138, need to clarify that one.

Suggest why Magnesium has a longer melting point than Bromine. (Something like that?)
-It has much more bonds than Bromine. So more bonds are needed to be broken when melting.
a) Calculate the mass of Ammonia in Q?
Basically use the ideal gas equation and usethe temp given, multiply the pressure by 1000 to convert it to SI Units, divide the volume by a million to convert to m^3 . Then use everything given to find the number of moles in Ammonia. Then find the mass of Ammonia using the mr.
b) Calculate the volume in P given that the temperature decreased by 5 degrees and the total pressure is 75kPa?
-Find volume of the whole system with the new values and use moles from previous question
-Then subtract from the volume of Q given.

Draw NH3 and AlCl3 and write the bonding angle.
NH3- 1 Lone pair and 3 bonding pair. Should have drawn a trigonal pyrimidal.
Bond angle- 107

AlCl3- 3 bonding pair so Trigonal Planar
Bond angle- 120

What type of bond between NH3 and AlCl3 to make 3HNAlCl3?
Dative covalent
Electron pair donated from NH2 to AlCl3.

Is there a new change in the bond angle around All in the 3HNAlCl3 and why?
Yes, bond angles decrease. As there is an extra bonding pair and they repel equally and as far apart as possible.

Half equation for chloride ion to chlorine?
2Cl- ---> Cl2 + 2e-
What is the half equation of Chlorate(I) into Chlorine?
2ClO- + 4H+ +2e- ---> Cl2 + 2H20

What is the redox equation of Sodium Chlorate(I) and HCl? You combined the two half equations
2Cl + 2CLO- +4H ---> 2CL2 + 2H2O

What's the observation when colourless Potassium iodide and Sodium Chloride are mixed and what reaction occurred for this to be seen?
There was a brown solution seen, as Iodine ion was reduced to Iodine.

Question on Anhydrous Magnesium Chloride and Anhydrous Barium Chloride mixture. Water was added and Sulphuric acid too. White precipitate was formed. What was this an find percentage of Magnesium in mixture?
Barium Sulphate.
Calculation:

Multiple Choices:
-Brown Colour is from the Reactant and forward is exothermic.
-Empirical of hydrocarbon with 9/11th Carbon- C3H8
-Doubts about biggest dipole. I put down BF3 and checked in my CGP book and states that bonds with electronegativity differences would make a dipole. Others argue that its Carbon one because BF3 is not polar.
-Group 2's ionisation energy decreases downwards
-There's 50cm^3 of gas in the end.
-Gold is 19.3
-SiO2 was Macromolecular
-Balance was 4:7
-The reducing agent was C204
-How much sulphuric acid needed? D
-Heavier isotope took longer in ToF
-H2 Molecules was 1.81* 10^24
(edited 7 years ago)

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Reply 1
Question 8 was redox and chlorine
I dont know why i revised for that exam, there was hardly anything i learnt on there
Aqa i give up😡😡😡
Original post by UnoGambino
I dont know why i revised for that exam, there was hardly anything i learnt on there
Aqa i give up😡😡😡


It's okay, you have another chance in paper 2, you can know learn from you mistakes. I got some questions wrong too. Hopefully the grade boundaries are going be low.

Posted from TSR Mobile
Reply 4
Original post by DaVinciGirl
If you know anymore questions or answers please reply.
What is the full electronic configuration of Al? 1s2,2s2,2p6,3s2,3p1

What is the full electronic configuration for Cr+3? 1s2,2s2,2p6,3s2,3p6,3d3

What is the formula of the atom with same electronic configuration of Krypton 2+?
Sr (strontium)

What compound has a +2 and -3 ions and has the same number electrons as Argon?
Ca2P3

Which ion has a smaller atomic radius Mg2+ or Na+?
Mg 2+
because has the same number of electrons, same shielding but more protons. So greater nuclear charge and attraction for outer electrons.

What is the first ionisation energy of Na?
Na (g) --> Na+ (g) + e-
Diagram-Mark where the Mg or was it Si?
Was and then mark the point where Sulphur was on the First ionisation graph.
Mg/Si should have been above so the line was increasing.
Sulphur should have been below Phosphorus but above Silicon.

Why does Sulphur have a different first ionisation energy compared to Phosphorus?
-Both have same shielding and in the same orbital the 3p orbital
-Sulphur is paired with an electron in the 3p orbital whilst Phosphorus isn’t
-There’s repulsion between the negatively charged electrons
-So electrons are easier to remove

Why does Bromine have lower boiling point than Magnesium?
-Bromine has a simple molecular structure.
-There’s weak Van der Waals forces between molecules.
-So smaller amount of energy needed to break these forces.
-Magnesium has a metallic lattice.
-It has many strong metallic bonds.
-Bonds formed from the strong attraction between positiveions and delocalised electrons.
-The metallic bonds are stronger than the Van der Waals forces

How do the ions get accelerated, detected by TIF and how abundanceis measured?
- Accelerated by negative electric field
-The ions reach the detector andgenerate a small current, which is fed to a computer for analysis. The currentis produced by electrons transferring from the detector to the positive ions.The size of the current is proportional to the abundance of the species.

Suggest why Magnesium has a longer melting point than Bromine. (Something like that?)
-It has much more bonds than Bromine. So more bonds are needed to be broken when melting.
a) Calculate the mass of Ammonia in Q?
Basically use the ideal gas equation and usethe temp given, multiply the pressure by 1000 to convert it to SI Units, divide the volume by a million to convert to m^3 . Then use everything given to find the number of moles in Ammonia. Then find the mass of Ammonia using the mr.
b) Calculate the volume in P given that the temperature decreased by 5 degrees and the total pressure is 75kPa?
-Find volume of the whole system with the new values and use moles from previous question
-Then subtract from the volume of Q given.

Draw NH3 and AlCl3 and write the bonding angle.
NH3- 1 Lone pair and 3 bonding pair. Should have drawn a trigonal pyrimidal.
Bond angle- 107

AlCl3- 3 bonding pair so Trigonal Planar
Bond angle- 120
What type of bond between NH3 and AlCl3 tomake 3HNAlCl3?Dative covalentElectron pair donated from NH2 to AlCl3.


Are you sure its Mg2+ I'm sure It's Na+ which has the smaller ion
Reply 5
Original post by DaVinciGirl
It's okay, you have another chance in paper 2, you can know learn from you mistakes. I got some questions wrong too. Hopefully the grade boundaries are going be low.

Posted from TSR Mobile


It won't be below 80% unfortunately.
Reply 6
Original post by DaVinciGirl
If you know anymore questions or answers please reply. Let me know if I made any mistakes :smile:
What is the full electronic configuration of Al? 1s2,2s2,2p6,3s2,3p1

What is the full electronic configuration for Cr+3? 1s2,2s2,2p6,3s2,3p6,3d3

What is the formula of the atom with same electronic configuration of Krypton 2+?
Sr (strontium)

What compound has a +2 and -3 ions and has the same number electrons as Argon?
Ca2P3

Which ion has a smaller atomic radius Mg2+ or Na+?
Mg 2+
because has the same number of electrons, same shielding but more protons. So greater nuclear charge and attraction for outer electrons.

What is the first ionisation energy of Na?
Na (g) --> Na+ (g) + e-
Diagram-Mark where the Mg or was it Si?
Was and then mark the point where Sulphur was on the First ionisation graph.
Mg/Si should have been above so the line was increasing.
Sulphur should have been below Phosphorus but above Silicon.

Why does Sulphur have a different first ionisation energy compared to Phosphorus?
-Both have same shielding and in the same orbital the 3p orbital
-Sulphur is paired with an electron in the 3p orbital whilst Phosphorus isn’t
-There’s repulsion between the negatively charged electrons
-So electrons are easier to remove

Why does Bromine have lower boiling point than Magnesium?
-Bromine has a simple molecular structure.
-There’s weak Van der Waals forces between molecules.
-So smaller amount of energy needed to break these forces.
-Magnesium has a metallic lattice.
-It has many strong metallic bonds.
-Bonds formed from the strong attraction between positiveions and delocalised electrons.
-The metallic bonds are stronger than the Van der Waals forces

How do the ions get accelerated, detected by TIF and how abundanceis measured?
- Accelerated by negative electric field
-The ions reach the detector andgenerate a small current, which is fed to a computer for analysis. The currentis produced by electrons transferring from the detector to the positive ions.The size of the current is proportional to the abundance of the species.

Suggest why Magnesium has a longer melting point than Bromine. (Something like that?)
-It has much more bonds than Bromine. So more bonds are needed to be broken when melting.
a) Calculate the mass of Ammonia in Q?
Basically use the ideal gas equation and usethe temp given, multiply the pressure by 1000 to convert it to SI Units, divide the volume by a million to convert to m^3 . Then use everything given to find the number of moles in Ammonia. Then find the mass of Ammonia using the mr.
b) Calculate the volume in P given that the temperature decreased by 5 degrees and the total pressure is 75kPa?
-Find volume of the whole system with the new values and use moles from previous question
-Then subtract from the volume of Q given.

Draw NH3 and AlCl3 and write the bonding angle.
NH3- 1 Lone pair and 3 bonding pair. Should have drawn a trigonal pyrimidal.
Bond angle- 107

AlCl3- 3 bonding pair so Trigonal Planar
Bond angle- 120
What type of bond between NH3 and AlCl3 tomake 3HNAlCl3?Dative covalentElectron pair donated from NH2 to AlCl3.


Did you get C3H8 or CH3?
Original post by Cinna21
Are you sure its Mg2+ I'm sure It's Na+ which has the smaller ion



The one with the greater number of protons. More protons means that the nucleus has a greater positive charge, which pulls the electrons in more. So, it is the magnesium ion.
Reply 8
Original post by SANTR
It won't be below 80% unfortunately.


I think it should be
Reply 9
Original post by DaVinciGirl
The one with the greater number of protons. More protons means that the nucleus has a greater positive charge, which pulls the electrons in more. So, it is the magnesium ion.


Argh I did that question too quickly I should of slowed down :frown: Oh well.
Shouldn't it be Ca3P2? And the half equation for sodium (I) chlorate have +2e-?
Original post by liziepie
Shouldn't it be Ca3P2? And the half equation for sodium (I) chlorate have +2e-?

Oops, you're right.
I did the PQ question differently too, not sure if it was right. Use the moles from the previous part to work out the new number of moles in Q given the new temp and pressure. Then, take the new moles away from the old moles value to give you the moles in P, then work out V=nrt/p with the new value. Got something like 377cm3 which was less than 1000cm3 in Q so it sounded right
There was a question about the mass spec of Br. I drew a line at 168 at 25%, 170 at 50% and 172 at 25% (mr might be wrong). And there was a whole section on Cu+ ions and working out the mass and velocity that I can't remember :smile:
Original post by liziepie
I did the PQ question differently too, not sure if it was right. Use the moles from the previous part to work out the new number of moles in Q given the new temp and pressure. Then, take the new moles away from the old moles value to give you the moles in P, then work out V=nrt/p with the new value. Got something like 377cm3 which was less than 1000cm3 in Q so it sounded right

Shouldn't the moles be the same as there is no NH2 taken away? I'm not quite sure though.
Original post by DaVinciGirl
Shouldn't the moles be the same as there is no NH2 taken away? I'm not quite sure though.


Hmm, don't know :frown: I thought I did way too much working for 3 marks, maybe I over complicated it. what answer did you get?
Reply 16
Original post by DaVinciGirl
Shouldn't the moles be the same as there is no NH2 taken away? I'm not quite sure though.


It was 3 marks - i doubt it was anything so complicated. I took is as a normal pv=nRT - 1 mark for conversion, 1 mark for new the intermediate eq and 1 mark for answer :smile:
Original post by liziepie
Hmm, don't know :frown: I thought I did way too much working for 3 marks, maybe I over complicated it. what answer did you get?


No sorry, I forgot. :redface:
for the Sr question (q3 i put Sr2+) will i still get the mark because I'm sure it asked for an ion?
QUOTE=DaVinciGirl;65238413]If you know anymore questions or answers please reply and the number of marks.
What is the full electronic configuration of Al? 1s2,2s2,2p6,3s2,3p1

What is the full electronic configuration for Cr+3? 1s2,2s2,2p6,3s2,3p6,3d3

What is the formula of the atom with same electronic configuration of Krypton 2+?
Sr (strontium)

What compound has a +2 and -3 ions and has the same number electrons as Argon?
Ca3P2

Which ion has a smaller atomic radius Mg2+ or Na+?
Mg 2+
because has the same number of electrons, same shielding but more protons. So greater nuclear charge and attraction for outer electrons.

What is the first ionisation energy of Na?
Na (g) --> Na+ (g) + e-
Diagram-Mark where the Mg or was it Si?
Was and then mark the point where Sulphur was on the First ionisation graph.
Mg/Si should have been above so the line was increasing.
Sulphur should have been below Phosphorus but above Silicon.

Why does Sulphur have a different first ionisation energy compared to Phosphorus?
-Both have same shielding and in the same orbital the 3p orbital
-Sulphur is paired with an electron in the 3p orbital whilst Phosphorus isn’t
-There’s repulsion between the negatively charged electrons
-So electrons are easier to remove

Why does Bromine have lower boiling point than Magnesium?
-Bromine has a simple molecular structure.
-There’s weak Van der Waals forces between molecules.
-So smaller amount of energy needed to break these forces.
-Magnesium has a metallic lattice.
-It has many strong metallic bonds.
-Bonds formed from the strong attraction between positiveions and delocalised electrons.
-The metallic bonds are stronger than the Van der Waals forces

How do the ions get accelerated, detected by TIF and how abundanceis measured?
- Accelerated by negative electric field
-The ions reach the detector and generate a small current, which is fed to a computer for analysis. The current is produced by electrons transferring from the detector to the positive ions. The size of the current is proportional to the abundance of the species.

Calculation to find mass of one ion.
1/Avogadro constant * mass. Then divide by 1000 to put it in Kg.
Using kinetic energy, find velocity.
Starts with 1........ Quite a large number.

Draw the spectrum of Br2 with two isotopes of equal abundance.
Screen Shot 2016-05-27 at 15.12.40.png

Suggest why Magnesium has a longer melting point than Bromine. (Something like that?)
-It has much more bonds than Bromine. So more bonds are needed to be broken when melting.
a) Calculate the mass of Ammonia in Q?
Basically use the ideal gas equation and usethe temp given, multiply the pressure by 1000 to convert it to SI Units, divide the volume by a million to convert to m^3 . Then use everything given to find the number of moles in Ammonia. Then find the mass of Ammonia using the mr.
b) Calculate the volume in P given that the temperature decreased by 5 degrees and the total pressure is 75kPa?
-Find volume of the whole system with the new values and use moles from previous question
-Then subtract from the volume of Q given.

Draw NH3 and AlCl3 and write the bonding angle.
NH3- 1 Lone pair and 3 bonding pair. Should have drawn a trigonal pyrimidal.
Bond angle- 107

AlCl3- 3 bonding pair so Trigonal Planar
Bond angle- 120

What type of bond between NH3 and AlCl3 to make 3HNAlCl3?
Dative covalent
Electron pair donated from NH2 to AlCl3.

What is the half equation of Chlorate(I) into Chlorine?
2ClO- + 4H+ +2e- ---> Cl2 + 2H20

What is the redox equation of Sodium Chlorate(I) and HCl?
I have no idea.

What's the observation when colourless Potassium iodide and Sodium Chloride are mixed and what reaction occurred for this to be seen?
There was a brown solution seen, as Iodine ion was reduced to Iodine.

Question on Anhydrous Magnesium Chloride and Anhydrous Barium Chloride mixture. Water was added and Sulphuric acid too. White precipitate was formed. What was this an find percentage of Magnesium in mixture?
Barium Sulphate.
Calculation:

Multiple Choices:
-Brown Colour is from the Reactant and forward is exothermic.
-Empirical of hydrocarbon with 9/11th Carbon- C3H8
-Doubts about biggest dipole. I put down BF3 and checked in my CGP book and states that bonds with electronegativity differences would make a dipole. Others argue that its Carbon one because BF3 is not polar.
-Group 2's ionisation energy decreases downwards
-There's 50cm^3 of gas in the end.
-Gold is 19.3
-SiO2 was Macromolecular
-Balance was 4:7
-The reducing agent was C204
-How much sulphuric acid needed? A
Original post by student1601
for the Sr question (q3 i put Sr2+) will i still get the mark because I'm sure it asked for an ion?


You're right, i just corrected it.

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