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Reply 900
The last question last 3 grid instructions were not clear

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Reply 901
Help to anyone who's making an unofficial mark scheme, some of the questions and marks given may not be right though:

1a) Define relative isotopic mass. (2)
1b) Fill the table in for the atomic structure of a potassium atom and ion. (3)
1c) How many molecules are in 6.(something)g of SiCl4? (3)
1d) Draw the symbols for each particle shown in the ionic lattice structure of KCl. (2)

A few other random questions I remember:
- Describe the reactivity of the group 2 metals with chlorine as you descend the group. (5)
- A precipitation reaction was used to identify the iodide present in Potassium Iodide. State the reagent used for this reaction (1)
- Write the ionic equation to show the reaction between this reagent and the Iodide ion. (1)
- A mixture of potassium iodide and bromine was present in a solution. What solvent can be used to identify the presence of iodide in this solution? (1)
- A student suggested the bond angles in H-N-H would be larger in NH3BF3 than NH3, suggest why. (3 marker I think)
- What bond angles are present in the F-B-F in: i) BF3 ii) NH3BF3 (2)
- Phosphene gas reacts with oxygen to form P4010 and water. Write out the equation for this reaction. (1)
- Why does PH3 have a lower boiling point than NH3? (1)
- Why is N2SO4 described as a salt? (1)
Reply 902
i made so many mistakes... aaagh
Reply 903
Was the ion oh- or clo-?
Reply 904
What did you do when it asked to calculate number of molecules

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Reply 905
Original post by Dejir
The last question last 3 grid instructions were not clear

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agreed so i wrote,attraction between positive ions and delocalised electrons for metal,covalent bonding between two atoms on carbon and vaan der wall forces/weak interm between two molecules
Original post by MichaelP96
LOL why didn't you go beforehand? I'm not 100% sure but it's 109.5. It asked for the H-N-H in the whole molecule? Unless I read it wrong :/


I did, but I have a small nervous bladder :colondollar:
Oww, I could have done that :mad: I wrote down all the angles for each number of bonded/lone pairs as soon as the exam started!
Original post by Dr. Django
Still an A regardless! I really want to know the answers a haha


Yeah, just need to work rather hard in my last 2 unit exams now.


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Reply 908
Original post by Dr. Django
Damn :/ originally I thought I'd done really well and now looking at this my hope is slowly slipping away...


Same. I felt quite good about this exam but I made such stupid mistakes. I told myself that I wasn't going to mentally torture myself by seeing what I got wrong, but I'm here anyway. I think I've lost atleast 8 marks. There goes my A.
Original post by MathsNerd1
Yeah, just need to work rather hard in my last 2 unit exams now.


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Same, i was really hoping i'd have a buffer...doesnt look like it tho :/
Original post by priya8D
Same. I felt quite good about this exam but I made such stupid mistakes. I told myself that I wasn't going to mentally torture myself by seeing what I got wrong, but I'm here anyway. I think I've lost atleast 8 marks. There goes my A.


so frustratin, although we dont yet know the definitive answers
1)i) The mass of an atom of an isotope of an element compared with 1/12th of the mass of an atom of carbon-12
ii) 41K+

Answers, in a random order ( can't remember question numbers)

-Volume of PH3 gas produced = 360cm^3
-Angles were 120* then 109.5*
-The student thought the angle would be larger because there are 4 bond pairs now (due to the dative covalent bond) giving a tetrahedral shape with 109.5* bond angle
-Group 2 reactions with chlorine were more vigorous as you went down the group because atomic radius increased and electron shielding increased making it easier to lose the outermost electrons
-Volume of NaOH i think it was, was 22.5cm^3
-Formula of reaction: Al203 (solid) + 3H2SO4 (aq.) ---> Al2(SO4)3 (aq.) + 6H20 (liquid)
-Main ions were Al(3+) and SO4(2-)
-Number of water molecules was 16
-1st Ionisation energy across period increased because nuclear charge increased and atomic radius decreased
-Number of SiCl4 molecules was 3.01*10^22
-Bleaching ion was ClO-
-Reaction of chlorine and water: Cl2 + H20 --> HCL + HCLO
-Litmus paper turned red because HCL is an acid
(edited 10 years ago)
Original post by Dr. Django
Same, i was really hoping i'd have a buffer...doesnt look like it tho :/


Just smash the next exam!!


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Original post by Liberty.
I did, but I have a small nervous bladder :colondollar:
Oww, I could have done that :mad: I wrote down all the angles for each number of bonded/lone pairs as soon as the exam started!


Should have gone during the exam?
I guess we all make stupid mistakes in the exam! i'm sure you've smashed it though!
Reply 914
For the ion that causes bleaching I put clo-
Seemed the most logical at the time?!
Reply 915
what did people get for the 2nd question with the box diagram
Original post by theCreator
1)i) The mass of an atom of an isotope of an element compared with 1/12th of the mass of an atom of carbon-12
ii) 41K+

Answers, in a random order ( can't remember question numbers)

-Volume of PH3 gas produced = 360cm^3
-Angles were 120* then 109.5*
-The student thought the angle would be larger because there are 4 bond pairs now (due to the dative covalent bond) giving a tetrahedral shape with 109.5* bond angle
-Group 2 reactions with chlorine were more vigorous as you went down the group because atomic radius increased and electron shielding increased making it easier to lose the outermost electrons
-Volume of NaOH i think it was, was 22.5cm^3
-Formula of reaction: Al203 (solid) + 3H2SO4 (aq.) ---> Al2(SO4)3 (aq.) + 6H20 (liquid)
-Main ions were Al(3+) and SO4(2-)
-Number of water molecules was 16
-1st Ionisation energy across period increased because nuclear charge increased and atomic radius decreased


I got all of that!


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Original post by Haque95
Help to anyone who's making an unofficial mark scheme, some of the questions and marks given may not be right though:

1a) Define relative isotopic mass. (2)
1b) Fill the table in for the atomic structure of a potassium atom and ion. (3)
1c) How many molecules are in 6.(something)g of SiCl4? (3)
1d) Draw the symbols for each particle shown in the ionic lattice structure of KCl. (2)

A few other random questions I remember:
- Describe the reactivity of the group 2 metals with chlorine as you descend the group. (5)
- A precipitation reaction was used to identify the iodide present in Potassium Iodide. State the reagent used for this reaction (1)
- Write the ionic equation to show the reaction between this reagent and the Iodide ion. (1)
- A mixture of potassium iodide and bromine was present in a solution. What solvent can be used to identify the presence of iodide in this solution? (1)
- A student suggested the bond angles in H-N-H would be larger in NH3BF3 than NH3, suggest why. (3 marker I think)
- What bond angles are present in the F-B-F in: i) BF3 ii) NH3BF3 (2)
- Phosphene gas reacts with oxygen to form P4010 and water. Write out the equation for this reaction. (1)
- Why does PH3 have a lower boiling point than NH3? (1)
- Why is N2SO4 described as a salt? (1)


Wasn't one of the last questions something to do with diamond or graphite?
Original post by MichaelP96
Should have gone during the exam?
I guess we all make stupid mistakes in the exam! i'm sure you've smashed it though!


I didn't know whether I'd have enough time, so I finished it and went in the last 15 minutes, and checked over it with a remaining 10 or so :tongue: luckily I had a nice invigilator. I hope so, I need my A. I had so much hope for this retake!
Original post by narli
Was the ion oh- or clo-?


I said OH- but the majority say CLO-