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Hard AS chemistry questions

A atomic emission spectroscopy
B infrared spectroscopy
C X-ray crystallography
D mass spectrometry
E electron diffraction

Which of A-E will;
6) determine the bond length and bond angles in a gaseous molecule by interaction with a stream of particles.
7) determine the palladium-gold interatomic distance in an alloy of palladium and gold.

9) Which of the following, in the solid state, has a crystal structure which contains discrete molecules? (one or more answers are correct)
1 MgO
2 CO2
3 SiO2
4 Rhombic sulphur

11) Which of the following can accect an electron pair in the formation of a dative covalent bond? (one or more answers are correct)
1 NH3
2 AlCl3
3 CH4
4 BF3

12) Delocalization of electrons may be expected in the species of formula
1 N2H4
2 NO3-
3 HNO3
4 NH4+

18) In which one of the following molecules would you expect to find the smallest angle between two adjacent covalent bonds? (1 answer only)
A BeH2
B BF3
C CCl4
D NH3
E OH2

26) Whihc of the following does not have a planar structure?
A NO3-
B H2CO
C NH3
D H2C=CH2
E BF3

30) The co-ordination numbers of Sr2+ and Cl- ion respectively are;
A 4:8
B 8:4
C 8:8
D 8:12
E 12:8

Never even heard of some of these terms. Why is my chemistry teacher doing this to me!!!! :mad:

Scroll to see replies

I'm really stuck. Can anyone help me?

Reply 3

Fade Into Black

Gosh... u sure they are AS level
im slightly baffled
lol.
There are onli parts i kno..
But Im not 100% certain

Reply 4

The Chameleon

Fade Into Black

Gosh... u sure they are AS level
im slightly baffled
lol.
There are onli parts i kno..
But Im not 100% certain

I'm baffled too. I have two multiple choice question papers (similar difficulty) to complete. My chemistry teacher lectures instead of teaches, and gives us ridiculously hard questions to do. E.g. majority fail.

Reply 5

hihihihi

a few guesses

The Chameleon

9) Which of the following, in the solid state, has a crystal structure which contains discrete molecules? (one or more answers are correct)
1 MgO
2 CO2
3 SiO2
4 Rhombic sulphur

what are 'discrete molecules'? I know that MgO has a crystal lattice

11) Which of the following can accect an electron pair in the formation of a dative covalent bond? (one or more answers are correct)
1 NH3
2 AlCl3
3 CH4
4 BF3

NH3 can

18) In which one of the following molecules would you expect to find the smallest angle between two adjacent covalent bonds? (1 answer only)
A BeH2
B BF3
C CCl4
D NH3
E OH2

H2O because it has 2 lone pair of electrons (electron repulsion theory)

26) Whihc of the following does not have a planar structure?
A NO3-
B H2CO
C NH3
D H2C=CH2
E BF3

NH3 is non planar (is a tetrahedron).

Reply 6

Fade Into Black

You reckon this stuff will be in our exam......
You do edexcel lik your brother dont you??

Reply 7

Ben.S.

hihihihi

NH3 can

Ammonia cannot. AlCl3 and BF3 can though.

Ben

Reply 8

john !!

18) In which one of the following molecules would you expect to find the smallest angle between two adjacent covalent bonds? (1 answer only)

E OH2 - because the oxygen has two lone pairs which repel more strongly than a covelant bond, I think the bond angle is 104.5 degrees.

26) Whihc of the following does not have a planar structure?

NH3 - the nitrogen has a lone pair in ammonia which will cause a pyramidal shape of the hydrogens..

Reply 9

hihihihi

Ben.S.

Ammonia cannot. AlCl3 and BF3 can though.

Ben

good point

Reply 10

Ben.S.

I would be tempted to say E for 6) and C for 7), although that might not be correct!

Ben

Reply 11

Ben.S.

For 12, the answer is 2.

Ben

Reply 12

Ben.S.

For 12, the answer is 2.

Ben

Er...and 3!

Ben

Reply 13

Wagamuffin

For questions 6, I think the answer may be E ( not at all certain); and for 7, A or C.

For question 11, it's 2 and 4 (this one's an easier Q; you just have to find the compounds in which an atom does not have a full shell after electron sharing)

For 26, I think it may be either A, E or both A and E.

Reply 14

The Chameleon

There are more evil questions I'm afraid.

A simple molecules only
B ions and simple molecules
C molecules (some of which are hydrogen bonded)
D molecules (some of which are hydrogen bonded and ions)
E ions and giant molecules

1. solution of ammonia in water
2. mixture of sodium chloride and sand
3. solution of benzene (C6H6) in toluene (C6H5CH3)
4. solution of acetic acid (CH3CO2H)
5. suspension of potassium bromide in toluene.

17) Which of the following compounds would you expect to have the largest dipole moment in the vapour phase?
A CH4
B NH3
C H2O
D NO
E HF

20) The following substances have approximately the same relative molecular mass. Which is likely to have the highest boiling point?
A CH3CH2CH2CH2CH3
B C2H5OC2H5
C CH3CH2CH2SH
D (CH3)2NC2H5
E CH3CH2CH2CH2OH

Good luck!

Reply 15

LS.

Which syllabus is this?

Reply 16

The Chameleon

LS.

Which syllabus is this?

i'm doing edexcel. I think my teacher knows that these questions are way too hard for the syllabus, but he's giving them to us anyway for extra practice.