AQA AS 2016 - CHEM1 (Resit) Unoffical Mark Scheme

Original post by koolgurl14

Question 1 b is electric field not magnetic field based on 2010 past paper.

1e Similarity : same relative abundance (or same height of peaks) Reason : same sample is used so similar amount of the isotopes are present . Difference is the m/z reason : High ionisation causes more than one electron knocked out so the charge is more than 1 so the mass of charge gets smaller so peaks will be to left of the graph.

The emperical formula it was Cu₃ (CO₃)₂OH it was clear from the question cause they told you at the start metal carbonate are based of the ions OH and CO3.

Are you sure? I got something like Cu3C2H2O8 cuz Cu came out as 1.5 so i just doubled to get whole number ratios, I dont think the order matters aslong as its empirical

Reply 67

Chembio123

7

Original post by SirRaza97

Here is my unofficial mark scheme. Anything in bold I am not sure if it's right. So if you have any idea then please tell me so i can add it! If i have missed anything out then aslo let me know!

Section A

1.
a) Relative Atomic mass Definition
b) Magnetic Field
c) - Ions accept electrons -Current is formed which is proportional to abundance
d) Something like 28.065 for the RAM
e) Similarity= Peaks still at original m/z values becuase +1 ions are still formed. Difference - Peaks at half the m/z values becasue high energy electrons will produce +2 ions

2. (Can't rmember what topic this was. I think it was about Van Der Waals)
a) -Electron Density randomly shifts -Creating areas of +ve and -ve charge on molecule - Attraction between molecules which is intermolecular force/VDW
b) O-H bond big electronegative difference allows for hydrogen bonds. Hydrogen bonds are stronger than VDW.
c) Fractional Distiallation will sperate these
d) The Se molecule is larger? This means the VDW forces are stronger between molecules

3. (Questions about Alkanes?)
a) Group is alkane
b) 2,2,4 - trimethylpentane (might accept 2,4,4 - trimethylpentane)
c) C₈H₁₈+ 12.5O₂------> 9H₂O + 8CO₂
d) but-1-ene
e) C₁₄H₃₀
f) Thermal Cracking. High temp and high pressure
g) Isomers question. Chain isomer = H₂C=C(CH₃)₂Postion isomer = But-2-ene Functional Isomer = Cyclic Alkane so cyclicbutane

4. (The weird reactions and the shapes question?)
a) Balancing equation I couldn't remember
b) Cu₂(OH)₂CO₃+ 4HCl -----> 2CuCl₂+ 3H₂O + CO₂
c) Effervescense
d) Something like Cu₃O₈H₂C₂
e) Shapes question - SF₆ = Octohedral , 90 degrees -SF₄= See-Saw shape. Lone pair on the horizontal plane. Angles 90, 120 or 180 degrees. Probably will accept -2.5 degrees off each angle.

Section B

5. (Period 3 stuff)
a) - Ionisation energies increase -Increasing proton number - Similar Shielding -Attraction between outer electron and nuclues gets stronger -The bigger nuclear charge reduces atomic radius (I don't think this point is needed)
b) -Silicon has highest melting point. -Because of macromolecular/Giant covelant structure. -Strong covelant bonds throughout structure. -Requires high amounts of energy to break.
c) The elements that you could say were Aluminuim because removing electron form 3p shell and Sulfur because of pair repulsion.
d) -Element Y is Sulphur. -Large jump in eneries from 6^th to 7^th ionisation enegies -So 7^th electron in inner shell so sulphur must be the element Y.

6. (Calculations)
a) 0.113m³(3 sig figs needed)
b) 1065 Kg or 1.065x10⁶g
c) Percentage yield = 49.3%
d) Method 1 because its 100% atom economy. Only producing one product.

For 4c I was going to wrie effervescence 😭😭 but I wrote a neutralisation occurred so salt is produced you wouldn't get the mark would u?

Reply 68

Chembio123

7

Original post by SirRaza97

Here is my unofficial mark scheme. Anything in bold I am not sure if it's right. So if you have any idea then please tell me so i can add it! If i have missed anything out then aslo let me know!

Section A

1.
a) Relative Atomic mass Definition
b) Magnetic Field
c) - Ions accept electrons -Current is formed which is proportional to abundance
d) Something like 28.065 for the RAM
e) Similarity= Peaks still at original m/z values becuase +1 ions are still formed. Difference - Peaks at half the m/z values becasue high energy electrons will produce +2 ions

2. (Can't rmember what topic this was. I think it was about Van Der Waals)
a) -Electron Density randomly shifts -Creating areas of +ve and -ve charge on molecule - Attraction between molecules which is intermolecular force/VDW
b) O-H bond big electronegative difference allows for hydrogen bonds. Hydrogen bonds are stronger than VDW.
c) Fractional Distiallation will sperate these
d) The Se molecule is larger? This means the VDW forces are stronger between molecules

3. (Questions about Alkanes?)
a) Group is alkane
b) 2,2,4 - trimethylpentane (might accept 2,4,4 - trimethylpentane)
c) C₈H₁₈+ 12.5O₂------> 9H₂O + 8CO₂
d) but-1-ene
e) C₁₄H₃₀
f) Thermal Cracking. High temp and high pressure
g) Isomers question. Chain isomer = H₂C=C(CH₃)₂Postion isomer = But-2-ene Functional Isomer = Cyclic Alkane so cyclicbutane

4. (The weird reactions and the shapes question?)
a) Balancing equation I couldn't remember
b) Cu₂(OH)₂CO₃+ 4HCl -----> 2CuCl₂+ 3H₂O + CO₂
c) Effervescense
d) Something like Cu₃O₈H₂C₂
e) Shapes question - SF₆ = Octohedral , 90 degrees -SF₄= See-Saw shape. Lone pair on the horizontal plane. Angles 90, 120 or 180 degrees. Probably will accept -2.5 degrees off each angle.

Section B

5. (Period 3 stuff)
a) - Ionisation energies increase -Increasing proton number - Similar Shielding -Attraction between outer electron and nuclues gets stronger -The bigger nuclear charge reduces atomic radius (I don't think this point is needed)
b) -Silicon has highest melting point. -Because of macromolecular/Giant covelant structure. -Strong covelant bonds throughout structure. -Requires high amounts of energy to break.
c) The elements that you could say were Aluminuim because removing electron form 3p shell and Sulfur because of pair repulsion.
d) -Element Y is Sulphur. -Large jump in eneries from 6^th to 7^th ionisation enegies -So 7^th electron in inner shell so sulphur must be the element Y.

6. (Calculations)
a) 0.113m³(3 sig figs needed)
b) 1065 Kg or 1.065x10⁶g
c) Percentage yield = 49.3%
d) Method 1 because its 100% atom economy. Only producing one product.

For 1e I wrote the similarity as the abundance but for the explanation I just wrote like it had to stay the same and I said a really stupid reason, not good scientific terminology at all, because like literally the abundance won't change lmao, would I still get the 2 marks?

Reply 69

shannon_1003

Original post by koolgurl14

Question 1 b is electric field not magnetic field based on 2010 past paper.

1e Similarity : same relative abundance (or same height of peaks) Reason : same sample is used so similar amount of the isotopes are present . Difference is the m/z reason : High ionisation causes more than one electron knocked out so the charge is more than 1 so the mass of charge gets smaller so peaks will be to left of the graph.

The emperical formula it was Cu₃ (CO₃)₂OH it was clear from the question cause they told you at the start metal carbonate are based of the ions OH and CO3.

i just looked at the AQA text book, they said "the deflection also depends on the magnetic field strength"
But you kind of right as well cuz I saw a question in past paper that wrote something about electric field

Reply 70

Applicant75235

12

Original post by Jackmilne95

Are you sure? I got something like Cu3C2H2O8 cuz Cu came out as 1.5 so i just doubled to get whole number ratios, I dont think the order matters aslong as its empirical

Yes you are right and i got that too but then you had to change it in the form of Cu CO3 and OH so in urs (which is like mine) Cu₃(CO₃)₂OH and if you count the number of carbons and hydrogens it is the same as your so u might get a mark for the working and u writing that but i think the question had 4/5 marks which is probably for writing it in this form instead

Reply 71

Pretty sure the question was asking for volume of phosphorus oxide so you would use mr of p4o10 and I got answer of 0.453m3

Posted from TSR Mobile

Reply 72

Original post by koolgurl14

Yes you are right and i got that too but then you had to change it in the form of Cu CO3 and OH so in urs (which is like mine) Cu₃(CO₃)₂OH and if you count the number of carbons and hydrogens it is the same as your so u might get a mark for the working and u writing that but i think the question had 4/5 marks which is probably for writing it in this form instead

Im probably being retarded and blind lol, but doesnt your answer only have 7 oxygens?

Reply 73

Got 49.30 for yield - 0.453 for gas equation - 1065 kg but u put G like an idiot! And yeah messed up ef messed up the 4 marks at start but I hope for a B

Posted from TSR Mobile

Reply 74

Original post by shannon_1003

i just looked at the AQA text book, they said "the deflection also depends on the magnetic field strength"
But you kind of right as well cuz I saw a question in past paper that wrote something about electric field

It's an electromagnet that's why. But i think the answer was magnetic

Reply 75

jaymistry233

Original post by koolgurl14

Question 1 b is electric field not magnetic field based on 2010 past paper.

1e Similarity : same relative abundance (or same height of peaks) Reason : same sample is used so similar amount of the isotopes are present . Difference is the m/z reason : High ionisation causes more than one electron knocked out so the charge is more than 1 so the mass of charge gets smaller so peaks will be to left of the graph.

The emperical formula it was Cu₃ (CO₃)₂OH it was clear from the question cause they told you at the start metal carbonate are based of the ions OH and CO3.

The answer in the 2010 past paper refered to the changing of velocity of the cations by altering the strength of the electric field generated by the negatively charged accelerating plates so that a spectrum of ions of different m/z ratios could be collected. The question asked how a full spectrum could be observed, changing the electric field strength was one of many factors.

Reply 76

Charco63

1

Original post by ahsan_ijaz

Pretty sure the question was asking for volume of phosphorus oxide so you would use mr of p4o10 and I got answer of 0.453m3

I got that but I divided 220g by 31(the Mr of P) but didn't look at the P4 bit so
Don't know whether it's right

Reply 77

Anyone else get
0.453
1.065kg and 43.90%

Posted from TSR Mobile

Reply 78

Original post by ahsan_ijaz

Anyone else get
0.453
1.065kg and 43.90%

Posted from TSR Mobile

I got 0.453 for gas question but i think thats wrong. it should be 1065kg i think. and yeh, shud be 43.9%

Reply 79