The Student Room Group

May 2015 OCR F321 may Unofficial MS.

** If your worrying about your answers DO NOT read the unofficial mark scheme as it is really UNRELIABLE, and real mark scheme may have all the points YOU wrote and nothing written below. And ofcourse the questions below are not in order**

1 a) table [2 marks]
140Ce2+ :
Protons: +1, 58
Neutrons: 0, 82
Electrons: -1, 56

1 b) name the other product [1 mark]
Hydrogen gas

1c) a) Formula of product formed (1)
Ce2(SO4)3

ci) What happens in terms of electron transfer (1)
Ce - gets oxidised from 0 to +3 (loses 3 electrons)

cii) Why is it a salt? (1)
H+ replaced my metal ion.

1 d) define 'emperical formula' [1 mark]
Simple whole number ratio (of atoms of elements in a compound.)

1 e) calculate the emperical formula [2 marks]
Tm2S3O12

1 f) How many electrons in the fourth shell? [1 mark]
32

1 g) How many orbitals in the third shell? [1 mark]
9

2. a) successive ionisation energies of aluminium [2 marks]
Jump between 3rd and 4th ionization and jump between 11th and 12th.

2. aii) equation for 3rd ionization energy of aluminum (1)
Al2+(g) -- > Al3+(g) + e-

2. b) define 'ionic lattice' [2 marks]
The attraction between oppositely charged ions held together by ionic bonds to form a giant ionic lattice.

2c) Define base and alkali using species. (2)
Base is H+ (proton acceptor)
Alkali soluble base that produces OH- ions in solution

2d) What reagent can be used to make calcium nitrate.
HNO3 reagent (1)

2e) Write the equation for this reaction.
2HNO3 + CaCO3 -> Ca(NO3)2 + H2O + CO2 (2)

2d) Chlorine gas is pumped into a solution of potassium iodide what will the student see? (1)
Colour change to brown

2f) Write an ionic equation for this reaction. (1)
Cl2(g) + 2I-(aq) ---> 2CL- (aq) + I2(aq)

2g) Cl2 + NaOH in cold conditions to form bleach. (1)
Cl2 + 2NaOH------> NaClO + H20+ NaCl

3 a) draw the dot and cross diagram for BBr3 [1 marks]
Same structure as BF3 but obvouisly f is replace by br lol.



ii)a) Write equation when fluorine reacts with aluminum. (1)
Al + 3/2 F2 --> AlF3

b)Draw AlF3 (2)
[Al]^3+ 3[F]^- (F should have at least on cross / dot)

3 b) Volume (2)
1080cm^3

3 c) explain the electrical conductivity of the following in solid and molten states [5 marks]
Metallic bonding = delocalised electrons therefore can conduct in both states
Covalent bonding = No delocalised electrons or mobile ions in both states. Therefore cannot conduct in both states.
Ionic bonding= Can conduct in molten due to mobile ions but not in solid due to absence of mobile ions.

3 d) define covalent bonding [1 mark]
Shared pair of electrons between two atoms.

3 e) Draw the 3D diagram of H2CCl2 and include the polarities [2 marks]
Both Cl slightly negative and Carbon slightly positive. Hydrogen no charge.

3 f) explain why this molecule is polar [1 mark]
No symmetry in molecule therefore dipoles do not cancel out.

3g) Define electronegativity (1)
measure of the ability of an atom to attract a pair of bonded electrons in a covalent bond.

3h) Electron configuration of manganese. (1)
[Ar] 4s2 3d5 (Both shorthand and longhand methods are fine).

3i) Why is this a Redox reaction (2)
Mn was reduced from +4 to +2 whilst Cl was oxidised from -1 to 0

4. [5 MARKS IN TOTAL]
a) 0.0018 (1)
b) 0.144 (1)
c) 0.0184mol (2)
d) 1.55g (1)

5. FLOWCHART GIVEN:

5 a) Thermal decomposition [1 mark]

5 b) Ca + 1/2 02 ---> CaO (1)

5 c) Ca(s) + 2H2O(l) -> Ca(OH)2 + H2 (1)

5cii) What would you observe for the above reaction? (1)
Fizzing / solid dissolves.

5 d) percentage calculation [1 mark]
55%

6.a)explain why the attraction between the nucleus and outermost electrons increases across a period? [2 marks]
- Shielding remains the same
- Nuclear charge increases as proton number increases.
- Atomic radius decreases
- Ionization energy increase.

6.b)explain in terms of the intermolecular forces present, the difference in melting points shown in the table [5 marks]
NH3 = Hydrogen bonding between molecules.
B2 AND F2 = Van der waal forces between molecules.
B2 has strong van der waal forces, stronger than F2. Van dar waals in bromine are stronger than the hydrogen bonds in ammonia therefore bromine has a higher boiling point as more energy required to overcome these forces.
B2 has stronger van der waals the F2 as it has more electrons (so more instantaneous dipoles are likely to occur).

I cant stress enough that this is just a rough mark scheme, real mark scheme will prob have loads of other points to get marks from.
(edited 8 years ago)

Scroll to see replies

Original post by FireFreak
** A few things left out cant remember question, also if your a person who worries about answers DO NOT read the unofficial mark scheme as it is really UNRELIABLE, and real mark scheme may have all the points YOU wrote and nothing written below.**

1 a) table [2 marks]
151Ce2+ :
Protons: +1, 58
Neutrons: 0, 93
Electrons: -1, 56

1 b) name the other product [1 mark]
Hydrogen gas

1 c) write the formula of the main product [1 mark]
- Cant remember the answer lol.

cii) What happens in terms of electron transfer (1)
Ce - gets oxidised from 0 to +3 (loses 3 electrons)

ciii) Why is it a salt? (1)
H+ replaced my metal ion.
1 d) define 'emperical formula' [1 mark]
Simple whole number ratio (of atoms of elements in a compound.)

1 e) calculate the emperical formula [2 marks]
Tm2S3O12

1 f) How many electrons in the fourth shell? [1 mark]
32

1 g) How many orbitals in the third shell? [1 mark]
9

2. a) successive ionisation energies of aluminium [2 marks]
Jump between 3rd and 4th ionization and jump between 11th and 12th.

2. b) define 'ionic lattice' [2 marks]
The attraction between oppositely charged ions held together by ionic bonds to form a giant ionic lattice.

2c) Define base and alkali using species. (2)
Base is H+ (proton acceptor)
Alkali soluble base that produces OH- ions in solution

2d) What reagent can be used to make calcium nitrate.
HNO3 reagent (1)

2e) Write the equation for this reaction.
2HNO3 + CaCO3 -> Ca(NO3)2 + H2CO3 (2)

2d) Chlorine gas is pumped into a solution of potassium iodide what will the student see?
Colour change to brown

2f) Write an ionic equation for this reaction. Ignore state symbols.
Cl2(g) + 2I-(aq) ---> 2CL-(aq) + I2(g)
3 a) draw the dot and cross diagram for BF3 [2 marks]



3 b) TITRATION CALCULATION [3 marks]
Need more info for this.. what was the question based on? cant remember.

3 c) explain the electrical conductivity of the following in solid and molten states [5 marks]
Metallic bonding = delocalised electrons therefore can conduct in both states
Covalent bonding = No delocalised electrons or mobile ions in both states. Therefore cannot conduct in both states.
Ionic bonding= Can conduct in molten due to mobile ions but not in solid due to absence of mobile ions.

3 d) define covalent bonding [1 mark]
Shared pair of electrons between two atoms.

3 e) Draw the 3D diagram of H2CCl2 and include the polarities [2 marks]
Both Cl slightly negative and Carbon slightly positive. Hydrogen no charge.

3 f) explain why this molecule is polar [1 mark]
No symmetry in molecule therefore dipoles do not cancel out.

4. THERE WERE 5 CALCULATIONS [5 MARKS IN TOTAL]
a) 0.144
b) cant remember
c) 0.0184mol
d) 1.55g

5. FLOWCHART GIVEN:

5 a) Thermal decomposition [1 mark]

5 b) Ca + 1/2 02 ---> CaO

5 c) CaCO3 --> CaO + CO2

5 d) percentage calculation [1 mark]
55%

6.a)explain why the attraction between the nucleus and outermost electrons increases across a period? [3 marks]
- Shielding remains the same
- Nuclear charge increases as proton number increases.
- Atomic radius decreases
- Ionization energy increase.

6.b)explain in terms of the intermolecular forces present, the difference in melting points shown in the table [6 marks]
NH3 = Hydrogen bonding between molecules.
B2 AND F2 = Van der waal forces between molecules.
B2 has strong van der waal forces, stronger than F2. Van dar waals in bromine are stronger than the hydrogen bonds in ammonia therefore bromine has a higher boiling point as more energy required to overcome these forces.
B2 has stronger van der waals the F2 as it has more electrons (so more instantaneous dipoles are likely to occur).

If anyone remembers any other questions or answers please feel free to post below. This is just a rough mark scheme, real mark scheme will prob have loads of other points to get marks from.


Legend :biggrin:
Reply 2
Been waiting for this! Thanks!
3A wasnt BF3 it was B BR3 and there was another question which was AlF3
Reply 4
Question 1a for neutrons is 0, 82?
http://www.chemicalelements.com/elements/ce.html

also for 2f im not sure if I2 is a gas, I would have thought it was aqueous but idk
(edited 8 years ago)
Reply 5
Original post by jonnypdot
3A wasnt BF3 it was B BR3 and there was another question which was AlF3


Got you thanks! (cant draw structue of BBr3 on here but it looks exactly like BF3 but obv with Br instead of F).
Original post by FireFreak
** A few things left out cant remember question, also if your a person who worries about answers DO NOT read the unofficial mark scheme as it is really UNRELIABLE, and real mark scheme may have all the points YOU wrote and nothing written below. And ofcourse the questions below are not in order**

1 a) table [2 marks]
151Ce2+ :
Protons: +1, 58
Neutrons: 0, 93
Electrons: -1, 56

1 b) name the other product [1 mark]
Hydrogen gas

1 c) write the formula of the main product [1 mark]
- Cant remember the answer lol.

cii) What happens in terms of electron transfer (1)
Ce - gets oxidised from 0 to +3 (loses 3 electrons)

ciii) Why is it a salt? (1)
H+ replaced my metal ion.
1 d) define 'emperical formula' [1 mark]
Simple whole number ratio (of atoms of elements in a compound.)

1 e) calculate the emperical formula [2 marks]
Tm2S3O12

1 f) How many electrons in the fourth shell? [1 mark]
32

1 g) How many orbitals in the third shell? [1 mark]
9

2. a) successive ionisation energies of aluminium [2 marks]
Jump between 3rd and 4th ionization and jump between 11th and 12th.

2. b) define 'ionic lattice' [2 marks]
The attraction between oppositely charged ions held together by ionic bonds to form a giant ionic lattice.

2c) Define base and alkali using species. (2)
Base is H+ (proton acceptor)
Alkali soluble base that produces OH- ions in solution

2d) What reagent can be used to make calcium nitrate.
HNO3 reagent (1)

2e) Write the equation for this reaction.
2HNO3 + CaCO3 -> Ca(NO3)2 + H2CO3 (2)

2d) Chlorine gas is pumped into a solution of potassium iodide what will the student see?
Colour change to brown

2f) Write an ionic equation for this reaction. Ignore state symbols.
Cl2(g) + 2I-(aq) ---> 2CL-(aq) + I2(g)
3 a) draw the dot and cross diagram for BF3 [2 marks]




3 b) TITRATION CALCULATION [3 marks]
Need more info for this.. what was the question based on? cant remember.

3 c) explain the electrical conductivity of the following in solid and molten states [5 marks]
Metallic bonding = delocalised electrons therefore can conduct in both states
Covalent bonding = No delocalised electrons or mobile ions in both states. Therefore cannot conduct in both states.
Ionic bonding= Can conduct in molten due to mobile ions but not in solid due to absence of mobile ions.

3 d) define covalent bonding [1 mark]
Shared pair of electrons between two atoms.

3 e) Draw the 3D diagram of H2CCl2 and include the polarities [2 marks]
Both Cl slightly negative and Carbon slightly positive. Hydrogen no charge.

3 f) explain why this molecule is polar [1 mark]
No symmetry in molecule therefore dipoles do not cancel out.

4. THERE WERE 5 CALCULATIONS [5 MARKS IN TOTAL]
a) 0.144
b) cant remember
c) 0.0184mol
d) 1.55g

5. FLOWCHART GIVEN:

5 a) Thermal decomposition [1 mark]

5 b) Ca + 1/2 02 ---> CaO

5 c) CaCO3 --> CaO + CO2

5 d) percentage calculation [1 mark]
55%

6.a)explain why the attraction between the nucleus and outermost electrons increases across a period? [3 marks]
- Shielding remains the same
- Nuclear charge increases as proton number increases.
- Atomic radius decreases
- Ionization energy increase.

6.b)explain in terms of the intermolecular forces present, the difference in melting points shown in the table [6 marks]
NH3 = Hydrogen bonding between molecules.
B2 AND F2 = Van der waal forces between molecules.
B2 has strong van der waal forces, stronger than F2. Van dar waals in bromine are stronger than the hydrogen bonds in ammonia therefore bromine has a higher boiling point as more energy required to overcome these forces.
B2 has stronger van der waals the F2 as it has more electrons (so more instantaneous dipoles are likely to occur).

If anyone remembers any other questions or answers please feel free to post below. This is just a rough mark scheme, real mark scheme will prob have loads of other points to get marks from.



You are such a legend!!!! , there was one question when you reacted chlorine with a sodium base to produce NaClO , was it

Cl2 + 2NaOH------> NaClO + H20+ NaCl?
Just a couple of points/questions:
2e) is H2O + CO2 for the end products (not H2CO3)
Also, in 2f) are you sure the I2 produced is gaseous? I put (aq) because it said a solution formed I think?

Thanks for the mark scheme though
Original post by luckycactus1337
You are such a legend!!!! , there was one question when you reacted chlorine with a sodium base to produce NaClO , was it

Cl2 + 2NaOH------> NaClO + H20+ NaCl?


That, sir, is correct.
Reply 9
There was the Europium and oxygen gas question, anyone else get 1080 cm^3
Reply 10
Original post by lukejoshjames
Legend :biggrin:


There was two ionic drawings the Alfl3 molecule that was 2 marks
1 marks for the equation between Aluminum and fluorine
Why is it that h2 is produced not h20 for the first question?
Original post by GMQ
Question 1a for neutrons is 0, 82?
http://www.chemicalelements.com/elements/ce.html

also for 2f im not sure if I2 is a gas, I would have thought it was aqueous but idk


I put what down what you just said :erm:
Reply 13
Original post by GMQ
Question 1a for neutrons is 0, 82?
http://www.chemicalelements.com/elements/ce.html

also for 2f im not sure if I2 is a gas, I would have thought it was aqueous but idk


Got you thanks, changed it!
Reply 14
Original post by RMur
There was the Europium and oxygen gas question, anyone else get 1080 cm^3


yes i got that too
Reply 15
I2 was aqueous because otherwise it wouldn't have affected the colour of the solution
Reply 16
Original post by RMur
There was the Europium and oxygen gas question, anyone else get 1080 cm^3


Yeah I got that to
Original post by virtualpainter
Why is it that h2 is produced not h20 for the first question?


Do you remember what the actual question was asking?
Original post by Missy1x
Yeah I got that to


Pretty sure it was 4000 something
Reply 19
Original post by FireFreak
Got you thanks, changed it!


well thank you for typing up this marscheme :biggrin:

Quick Reply

Latest