2007 Chemistry Exam 2 Written Examination

[Collin Li]

Coblin you are my hero

Can you send me photos of you so I can put them up around my room and worship you?

No, seriously, thanks so much for doing this.

Don't forget. We have to thank asa.hoshi for the quick supply of the paper. I want to ask though, was there any information omitted from Q15 and 16 of the multi-choice? My reasoning is deductive rather than constructive. I've only eliminated instead of actually figured out the answer.

Thanks asa.hoshi!

[asa.hoshi]

I want to ask though, was there any information omitted from Q15 and 16 of the multi-choice? My reasoning is deductive rather than constructive. I've only eliminated instead of actually figured out the answer.

lol sorry. there is some info. i remember typing it up. but somehow it got deleted. i type it up again. here ya go!

Questions 15 and 16 refer to the following information.

A rechargeable cell, used in laptop computers, contains a metal allow (designated M) which has hydrogen atoms adsorbed on its surface. and nickel in the form of NiO(OH) (s) and Ni(OH)2(s).

The half reactants, written as reduction reactions, are
H2O(l) + e- <--> H (adsorbed on M) + OH-(aq)
NiO(OH)(s) + H2O(l) + e- <--> Ni(OH)2(s) + OH-(aq)

While this cell is generating electricity, the metal alloy acts as the negative electrode.

Question 15
When this cell is generating electricity
A. NiO(OH) acts as the oxidant
B. the concentration of OH-ions in the cell increases as the cell discharges
C. OH- ions produced at the negative electrode migrate to the positive electrode.
D. electrons flow in the external circuit from the positive to the negative electrode.

Question 16
When the cell is recharged, which one of the following precesses occurs at the electrode connected to the positive terminal of the external power source?
A. reduction of H2O(l)
B. reduction of NiO(OH)(s)
C. oxidation of Ni(OH)2(s)
D. oxidation of H (adsorbed on M)

[Collin Li]

Alright, cool

Thanks again!

[asa.hoshi]

Alright, cool

Thanks again!

no probs. its a good way of getting my post-count up. maybe i should of made each multiple choice question 1 post. LOL  :lol:

[kido_1]

CHEMISTRY
Written examination 2
Thursday 15 November 2007

SECTION A - Multiple-choice question
Question 1
IN which one of the following compounds does the transition metal display the lowest oxidation state?
A. CrO3
B. Cu2S
C. MnCl2
D. K2Cr2O7

Question 2
Consider the following nuclear reaction that takes place in stars.
8\4Be + 4\2He  --> 12\6C
Which of the following statements about this change is/are correct?
I. The reaction is endothermic
II. The mass of the 12\6 nucleus is greater than the combined masses of the reactants.
A. I only
B. II only
C. both I and II
D. neither I nor II

Question 3
Some information about the element rhenium (Re) is given in the table below.
Isotope            Relative isotopic mass
185Re                          185.0
187Re                          187.0
Given that the relative atomic mass of Re is 186.2, the percentage abundance of 187Re is closest to
A. 40
B. 50
C. 60
D. 70

Question 4
A solution prepared by stirring Na2O(s) in water undergoes an acid-base reaction with a solution prepared from SO3(g) and water.
Which one of the following salts could be isolated from the reaction mixture?
A. Na2S
B. NaHSO3
C. Na2SO3
D. Na2SO4

Question 5
Which one of the following alternatives contains molecules and ions that are all likely to form a complex ion with a transition metal cation.
A. Cl-, F-, CN-, H+
B. NH3, Cl-, F-, H20
C. Na+, CN-, F-, H20
D. CH4, Cl-, NH3, H20

Question 6
Predict which one of the following compounds would be coloured.
A. BaSO4
B. AlPO4
C. KClO4
D. NaMnO4

Question 7
Which of the following statements about enzymes are correct?
I. Enzymes are proteins.
II. Enzymes increase the rate of biochemical reactions.
III. Enzymes increase the equilibrium constant of biochemical reactions.
A. I and II only
B. I and III only
C. II and III only
D. I, II and III

Question 8
A structure of Vitamin C is given below:

Vitamin C is an important biological molecule. It is often added to foods as an antioxidant. Based on this information, and on the structure of Vitamin C shown above, it can be predicted that vitamin C is more soluble in
A. fats than in water and is a good oxidant
B. fats than in water and is a good reductant
C. water than in fats and is a good oxidant
D. water than in fats and is a good reductant

Question 9
The types of compounds that comprised the major food groups include carbohydrates, fats and proteins. A sample, containing only one of these three types of compounds, is analyzed and found to contain the following
Carbon: 76.2%
Oxygen: 11.3%
Nitrogen: 0%
The compound
A. is likely to be a fat
B. is likely to be a protein
C. is likely to be a carbohydrate
D. cannot be identified as the percentage composition of other elements has not been given.

Question 10
The follow two unbalanced equations represent process which are part of the nitrogen cycle.
I. NH3 (aq) --> NH4+ (aq)
II. NH4+ (aq) --> NO3-(aq)
Which one of the following alternatives correctly describes the reactants in each of these processes?
   In process I, NH3(aq) is... In process II, the NH4+(aq) ion is
A. an acid...reduced
B. a base...reduced
C. an acid...oxidised
D. a base...oxidised

Wow. Talk about dedication. It seems from this test that some things I learnt in bio might actually pop up in chem next year.

[golids]

kido if you have a whole AOS on food chem bio will without a doubt be handy. i barely had to go over food chem

[kido_1]

It is the opposite way around.

Bio will help me out in chem.

That is the only good thing that could come out of bio, seeing i stuffed Exam 2 up.

[karina]

wow asa.hoshi thats so nice of you!