F321 Updated Unofficial Mark Scheme Watch

Mr van der WAALs
Badges: 1
Rep:
?
#1
Report Thread starter 8 years ago
#1
An updated version of the F321 mark scheme ~ Friday 21st May 2010

F321 ~ Unofficial Mark Scheme (Updated version)

Answers to Question 1:

a) 50 68 50 ~ proton, neutrons and electrons of Tin (Sn) [1]

b) The weighted mean mass; of an atom of an element compared; to 1/12th of the carbon-12 isotope; [3]

c) 120 Sn has 2 more neutrons than 118 Sn [1]

d) 2.08kg = 2080/118.7 =17.52
17.52 x 6.02 x 10^23 =1.05 x10^25 [2]

e) 78.8% of Sn and 21.2% O2; therefore SnO2 [2]

Answers to Question 2:

a) H+ and SO4 2- [2]

b) bubbles/fizzing of gas (CO2); solid carbonate dissolves;

K2CO3 + H2SO4 = K2SO4 + CO2 + H2O; [3]

c) 2.47 x 10^-3 [1]

d) 4.94 x 10^-3 [1]

e) Since 2.00g of soda was used to make a 250cm^3 solution; then 25cm^3 was titrated against 24.70cm^3 of 0.100mol dm^3 H2SO4;

The calculation for the % mass was:

moles of NaOH ~ n= 2.00/40 = 0.05mol
moles of the amount titrated ~ n= (24.7 x 0.1)/1000 = 2.47 x 10^-3

2:1 reaction, hence; 4.94 x 10^-3 moles used in 25cm^-3
Therefore x10 gives 250cm^-3 = 0.0494

Then; 0.0494/0.05 = 0.988

0.988 x 100 = 98.8% [3]

Answers to Question 3:

a) 4s then 3d [1]

b) Orbital~ where two electrons 'spin'; opposite directions; eq [1]

c) 11 electrons in p-orbitals [1]

d) Ca 2+ = 18 electrons [1]

e) 2nd, 3rd, 10th and 11th [2]

f) Al (2+) (g) = Al (3+) (g) + e- [2]

Answers to Question 4:

a) purple/violet; orange [2]

b) displacement between Br and I; eq [1]

c) Cl simultanously oxidised and reduced;

From 0 to +1 in HClO;
From 0 to -1 in HCl; [3]

ii) Cl kills bacteria; eq [1]

d) thermal decomposition [1]

e) Calculation involving a carbonate; find volume of CO2;

I cannot really remember what my answer was; something like 17.4dm3 [2]

f) Thermal stability increases down the group; eq [1]

Answers to Question 5:

a) Lithium has giant metallic structure; diagram etc;

Fixed cations; surrounded by delocalised electrons; tightly packed/strong attractions; eq ~ high boiling point [3]

b) Fluorine covalently bonded; 8 electrons for each one [ 3 x lone pair]; one shared pair; eq [1]

c) LiF ~ Ionic structure ~ Li electron in outer shell completes the incomplete shell to leave Li with a full shell; and a + charge []; F with a full shell (show by dots and crosses); and a - charge []; eq [2]

d) Fails to conduct when solid; ions are fixed; conducts when molten; ions are delocalised; [2]

e) 2B + 3[F2] = 2[BF3] [1]

f) Trigonal planar; 120 degrees; 3 bonded pairs and no lone pairs; eq ~ repulsion theory explained; eq [4]

g) Permeanent dipoles arise due to difference in electronegativity; F very electronegative; electrons pulled closer; eq [3]

h) Atomic radii decrease across period 2; increased proton number; therefore increased nuclear charge; electrons added to same shell; similar shielding; hence atomic radii decrease; shells/electrons pulled closer/more strongly to nucleus; ionisation increases; eq [4]
1
reply
BAPURAMT
Badges: 0
#2
Report 8 years ago
#2
wow thats gr8!
0
reply
FoOtYdUdE
Badges: 0
Rep:
?
#3
Report 8 years ago
#3
Cheers dude.
0
reply
student53
Badges: 0
#4
Report 8 years ago
#4
do you have the mark scheme or answers to the F332 Jan 2010 paper?....natural resources...thanks
0
reply
Jawanda
Badges: 0
#5
Report 8 years ago
#5
Hi...Mr van der waals, i think u might have missed a few questions out or it could just be me.....the one where you had to write another displacement reaction, the actual thermal decomposition equation of magnesium carbonate, and what use is chlorate ions...i think! thank youu!
0
reply
baby-angel-x
Badges: 0
Rep:
?
#6
Report 8 years ago
#6
Hey you know Q1 part c.
What did the question ask?
I dont remember getting 118 etc, I swear it asked to compare two forms of sn, and one had 2 more neutrons :?
write back ppl x thanks
0
reply
codedmaster
Badges: 0
#7
Report 8 years ago
#7
What was the question about NF3 again as I don't remember the question about Lone pairs and bonded pairs.
0
reply
baby-angel-x
Badges: 0
Rep:
?
#8
Report 8 years ago
#8
(Original post by codedmaster)
What was the question about NF3 again as I don't remember the question about Lone pairs and bonded pairs.
Hey codedmaster. the question asked 'why does NF3 have a permanent dipole?' This question was straight after the BF3 question which asked you to write about bond angles etc.

I thought it was hard :/ I messed up ALL the calculations and I'm worrying :'(
0
reply
Mr van der WAALs
Badges: 1
Rep:
?
#9
Report Thread starter 8 years ago
#9
(Original post by baby-angel-x)
Hey you know Q1 part c.
What did the question ask?
I dont remember getting 118 etc, I swear it asked to compare two forms of sn, and one had 2 more neutrons :?
write back ppl x thanks

Hi...Mr van der waals, i think u might have missed a few questions out or it could just be me.....the one where you had to write another displacement reaction, the actual thermal decomposition equation of magnesium carbonate, and what use is chlorate ions...i think! thank youu!
Yeah your both right; I did put this together from memory so there is bound to be a few mistakes;

I shall edit the mistakes asap! :cool:

Thanks for your help!
0
reply
student53
Badges: 0
#10
Report 8 years ago
#10
anyone have the mark scheme to natural resoucres jan 2010 ocr salters b?
0
reply
BradfordCityJoss
Badges: 0
Rep:
?
#11
Report 8 years ago
#11
Fantastic. Thanks alot. I agree with all the marks there actually (well almost) so should be good.
0
reply
BradfordCityJoss
Badges: 0
Rep:
?
#12
Report 8 years ago
#12
(Original post by Mr van der WAALs)
An updated version of the F321 mark scheme ~ Friday 21st May 2010


3a) 4s then 3d [1]
Isn't the answer 3d 4p (As 4s was already there?)
0
reply
Mr van der WAALs
Badges: 1
Rep:
?
#13
Report Thread starter 8 years ago
#13
(Original post by BradfordCityJoss)
Isn't the answer 3d 4p (As 4s was already there?)
Maybe I cannot quite remember; but I thought it was trying to test if candidates knew the filling of shells order; 4s fills before 3d, I thought the last shell they put was 3p, then we had to put 4s then 3d. :confused:
0
reply
FoOtYdUdE
Badges: 0
Rep:
?
#14
Report 8 years ago
#14
(Original post by Mr van der WAALs)
Maybe I cannot quite remember; but I thought it was trying to test if candidates knew the filling of shells order; 4s fills before 3d, I thought the last shell they put was 3p, then we had to put 4s then 3d. :confused:
3d and then 4p was ansa if i remb cr3ectly
0
reply
BradfordCityJoss
Badges: 0
Rep:
?
#15
Report 8 years ago
#15
(Original post by FoOtYdUdE)
3d and then 4p was ansa if i remb cr3ectly
I agree, they were being kind. 4s was the last one, so I put down 3d 4p (this still shows if the candidate was 1) paying attention and spotted 4s 2) showing that they know 3d comes after 4s (but it does it with a prompt which is why I thought it was a kind question.
0
reply
baby-angel-x
Badges: 0
Rep:
?
#16
Report 8 years ago
#16
(Original post by BradfordCityJoss)
I agree, they were being kind. 4s was the last one, so I put down 3d 4p (this still shows if the candidate was 1) paying attention and spotted 4s 2) showing that they know 3d comes after 4s (but it does it with a prompt which is why I thought it was a kind question.
Are you SURE 4s was the last one.
I swear it went like 1s 2s 3s 3p then there were 2 gaps so i put 4s then 3d.

im screwed if i misread the table...lol i neva read Q's properly :/ x
0
reply
baby-angel-x
Badges: 0
Rep:
?
#17
Report 8 years ago
#17
(Original post by Mr van der WAALs)
Yeah your both right; I did put this together from memory so there is bound to be a few mistakes;

I shall edit the mistakes asap! :cool:

Thanks for your help!
hey mr van der waals
errmm..oh yh you know, the Q about why NF3 has a permanent dipole, I believe this question was worth 2 marks and NOT 3. ??
But thanks anywayy..goodjob
0
reply
BradfordCityJoss
Badges: 0
Rep:
?
#18
Report 8 years ago
#18
(Original post by baby-angel-x)
Are you SURE 4s was the last one.
I swear it went like 1s 2s 3s 3p then there were 2 gaps so i put 4s then 3d.

im screwed if i misread the table...lol i neva read Q's properly :/ x
I'm afraid so, I was happy becuase I remember thinking, do they want it in order of energy levels or just in order? then I saw 4s and saw they'd made the desicion for me.
0
reply
BA1
Badges: 0
Rep:
?
#19
Report 8 years ago
#19
Paper uploaded here:

http://rapidshare.com/files/391528080/f321.pdf
0
reply
BradfordCityJoss
Badges: 0
Rep:
?
#20
Report 8 years ago
#20
(Original post by BA1)
Paper uploaded here:

http://rapidshare.com/files/391528080/f321.pdf
Thanks for the share.
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

University open days

  • University of East Anglia
    All Departments Open 13:00-17:00. Find out more about our diverse range of subject areas and career progression in the Arts & Humanities, Social Sciences, Medicine & Health Sciences, and the Sciences. Postgraduate
    Wed, 30 Jan '19
  • Aston University
    Postgraduate Open Day Postgraduate
    Wed, 30 Jan '19
  • Solent University
    Careers in maritime Undergraduate
    Sat, 2 Feb '19

Brexit: Given the chance now, would you vote leave or remain?

Remain (1388)
79.59%
Leave (356)
20.41%

Watched Threads

View All
Latest
My Feed