AQA Chemistry Unit 1 - [23rd May 2014]AM

i wrote down combustion :'(

it also said compound so i assumed they both had to be different hence forming a compound. i put H3B though seen as their differnce was only 0.1

If anyone wants to finish this off, I've got to pop out.

Unofficial mark scheme

Question 1

ai) (1 mark) Proton + electron = 1.6734 x10-24g
aii)(1 mark) B – neutron
bi) (2 marks): 20% 10B, 80% 11B
bii) (1 mark) Same number of electrons
c) (1 mark): 50000 – 20000 (?)
d) (1 mark): B+ (g) -> B2+ (g) + e-

Question 2

ai) (1 mark): 0.00893
ai) (1 mark): 0.0270
aii) (4 marks) Volume of NO2 produced(5 marks)?: Convert T to K (1 mark); V= nRT/P; V/15 x12
b) (1 mark) (Thermal) Decomposition
c) (1 mark): The other products are gaseous and so will not react with the solid iron oxide.

Question 3
ai) (1 mark)d
aii) (2 marks) Metallic bonding (1 mark); electrostatic force/ attraction (1 mark); between delocalised electrons and Ni+ nucleus (1 mark)
aiii) (2 marks) 6 + particles; regular arrangement
iv) They are arranged in layers so they can be pulled over one another
bi) 1s2 2s2 2p6 3s2 3p6 3d8
bii) _ 6 _ 6 _ 12 CaCO3

Question 4
ai) (1 mark): Hydrogen
aii) (3 marks): Partial charges (1 mark), lone pairs (1 mark), bond from lone pair on N to H (1 mark)
b) (1 mark) N donates a pair of electrons
ci) (2 marks) Atoms ability to attract electron density (1 mark) in a covalent bond (1 mark)
cii) LiF
ciii) LiH (?)
Question 5
a) (1 mark): Crude oil (1 mark): Fractional distillation
b) (1 mark): C12H26 + 6O2 -> 12Co + 13H2 OR C12H26 + 7 12 ½ O2 -> 12CO + 13H2O (g)
ci) (2 marks) Hot temperature (1 mark) allows nitrogen and oxygen in air to react
cii) NO + ½O2 -> NO2
di) CnH2n+2
dii) Equation: C12H26 -> C6H12 + C6H14; C3H7; Zeolite
diii) Longer carbon chain = bigger surface area; stronger VDW; more energy


+

Name of compound (1 mark): 2,2,3,3,4,4-hexmethylhexane
Type of isomerism (1 mark): Chain (branched)
Question 6

Atom Economy = 71.6%

Find the concentration of HNO3: 1.23moldm-3

Find the value of x (4 marks): Ratio of elements, Ca = 1, H = 4, P = 2, O = 8 therefore x = 2

Question 7


Tl + ½ Br2 -> TlBr

I was thinking about this for ages but the question said formed by combination of two of the elements from the table, so I assumed they had to be different?

I put that at first, but im not sure whether its BH3 or CH4 because Boron and Hydrogen are both positive ions so I dont know if they would react :/
URGH - ive done some stupid stuff

Apparently BH3 does exist - wikipedia

Indeed it does.

I know we haven't been taught this yet, but a H atom can act as both a cation (like usual in an acid) and an anion.

Hence BH₃ is very much real.

Omg i completely forgot the fking last page!!!!!!!!!!!!!!!!!!! Fuk my life......this so so frustrating, i was hoping for an a but now im going to get a c................why did this happen??????????????????????? Im was soo piseed that i even went straight home after that exam....i cant take this anymore, i am going to have no life this whole week until unit2 starting from tomorrow......i need to make up for the 10 mark loss.....20ums points....fuk my life...im done, seriousily!!!!!!!!!!!!!!!!!!!!

this hasn't got anything to with ions its to do with covalent bonds

Mate sorry to tell you but hes drawn TlCl4 correct as its not titanium its thallium !!

Bit of a harsh question to ask!

Bit of a harsh question to ask!

It did say in the question that what would have the LEAST polar BOND, from two elements, I initially put BH3, but then reread the question and it said BOND, not MOLECULE. Therefore I was pretty certain it could only be two Atoms, therefore it had to be HB