This paper consists of 5 MCQ and 5 free r esponse questions. Complete all the questions below.
1) For H Atom, select the on e that best represent the electron level diagram.
a . S
d. none of the above
2) Which of the following is fa lse about MO theory?
a) no. of atomic orbital formed will be the sam e as the no. of molecular orbital form b) MO theory not only can be used to explain magnetic properties but as well as el ectrical conductivity c) MO diagram for carbon dioxide is the same as oxygen
d) A σ MO bond can be formed by either two atomic s-orbitals or two atomic pz-or rbitals
3) Which of the following cr iteria/s you need to look out for when finding the correct molecu le using formal charges. (C heck the boxes for the correct criteria/s)
sum of all formal charges must be equal to the charge of the molecule a more -ve formal charge should reside on a more electronegative atom smaller charges are preferred over large r ones
same non-zero formal charges on adjace nt atoms are not preferred
4)Hess law is applicable for the calculation of:
( b) Gibbs Free Energy
(d) All of the above
5) Which of the following is false?
(a) the reasons why ideal gas deviates could be due to significant molecular size and intermolecular attractions
(b) ideal gas is a combination of boyle and charles law only (c) ideal gas law is most accurate for monatomic gases at high temperatures and low pressures (d) none of the above
B2O3 (s) + 3H2O (g) → 3O2 (g) + B2H6 (g) (∆H = 2035 kJ/mol)
H2O (l) → H2O (g) (∆H = 44 kJ/mol)
H2 (g) + (1/2)O2 (g) → H2O (l) (∆H = -286 kJ/mol)
2B (s) + 3H2 (g) → B2H6 (g) (∆H = 36 kJ/mol)
Find the ∆Hf of:
2B (s) + (3/2) O2 (g) → B2O3 (s)
7) The picture below shows the struc ture of the enzyme amylase.
The highlighted orange circles are the act ive site which contains aspartate residues which are responsible for breaking the peptide b ond using the process known a s hydrolysis. This picture below shows the amino acid.
a) Suggest how the aspartic acid is responsible for breaking t he peptide bond in the protein.
b) Draw and the label the ene rgy profile diagram for this react ion. c) Suggest how the enzyme a ction can affect ∆G and ∆S and ex plain why is it so.
8) Bioluminescence is a common characteristics found in many living organisms for different function. One of it is the use of the protein luciferin and the enzyme luciferase as an aid in the production of light.
A simplified formula of the bioluminescent reaction:
ATP(energy) + Luciferin + Luciferase + O2(oxidizer) -> light (photons) a) Suggest how this reaction can result in the formation of light for the living organisms.
b) One of the bioluminescence is the sea firefly that produces the blue light and another would be railroad worms that emit red light. Given that blue light have a frequency of 606 x 1012 and 400 x x 1012 for the red light, calculate which
organism require more energy.
c) Given that hydrolysis of ATP result in ∆G = −30.5 kJ/mol calculate the number of ATP molecule needed for producing the blue light.
9) The diagram below shows the ion isation energy of an element X.
a) Describe and explain the trend of the ionisation energy of element X . b) State which group does the eleme nt X belongs to.
State and explain why the He isenberg Uncertainty Principle is only applicable for s
microscopic particles and not for the macro particles.