قسم الكيمياء .. المقالات ..

Analytical Chemistry

1- The uv-visible radiation region is between

a- 200-800 A b- 200-800 nm c- 400-800 A d-400-800 nm

2- If the fraction mole of metal is (0.66) the formula of complex is

a- ML b- ML2 c- M2L d-M2L3

3- A molar concentrated of aqueous ammonia that is 28.0% w/w NH₃ and has a density of 0.899 g/ml is

a- 14.8 b- 14.6 c- 14.2 d- 14.1

4- The pNa⁺ for solution results from mixing 10 ml of 1x10^-3 M Na₃PO₄ and 10 ml of 1x10^-3 M NaCl is

a- 3 b- 2.397 c- 2.522 d- 2.698

5- A 1.25 g of alloy was dissolved in acid and diluted to volume in a 250 ml volumetric flask. A 20 ml portion of the resulting solution was transferred by pipet to a 50 ml volumetric flask and diluted to volume. An analysis showed that the concentration of Cu²⁺ in final solution was 4.62 ppm. the weight percentage of Cu in the original alloy is

a- 0.115 b- 0.231 c- 0.345 d- 0.46

6- The electrode potential of the half-cell [ Bi|BiO⁺ (1x10^-3 M), H⁺( 1x10^-2M).] E⁰= 0.32 v is

a- 0.113 v b- 0.182 v c- 0.216 v d- 0.32 v

7- The number of moles of MnO₄^- needed to balancing the reaction of MnO₄^- with H₂O₂ to form Mn²⁺ , O₂ and H₂O is

a- 4 b- 3 c- 2 d- 1

8- If the t_m of mobile phase is 0.15 min and the t_R of compound is 3.23 min. the capacity factor is

a- 0.484 b- 3.08 c- 20.53 d- 21.53

9- On the a particular 25 cm long column. Benzene had a retention time of 33 min and a peak width of 15.1 min .the height equivalent of a theoretical plate is.

a- 0.027 b- 0.127 c- 0.227 d- 0.327

10- The pH of 0.1M NH₄Cl solution is (Kb_NH4OH= 1x10^-5)

a- 5 b- 7 c-8 d- 10

Physical chemistry

11- Newton’s second law of motion is ..............

a - F = -kx

b - -kx = mx^•

c - -kx = m

d- None of them

12- The equation ʌ̑f = λf is the Eigen function where λ is..............

a- Eigen value

b- linear operator

c- complex value

d- not Eigen value

13- Heisenberg`s uncertainty principle states that both the and ............. of a particle can`t be determined with finite accuracy and instantaneously.

a - momentum

b - mass

c - energy

d – time

14- The Hamiltonian operator is the.............. factor.

a - moment

b - time

c - energy

d – potential energy

15- For the reaction 2A + 3B → 4C + 5D, the reaction rate could be expressed in terms of ΔA as..............

a - -ΔA/Δt.

b - -0.5 ΔA/Δt.

c - +ΔA/Δt.

d - +0.5 ΔA/Δt.

16- The energy needed for a reaction to proceed from reactants to products is called is..............

a - collision energy

b - Kinetic energy

c - activation energy

d - potential energy

17- In a voltaic cell, electrons flow from the ..............to the...............

a - Salt bride, anode

b - Anode, cathode

c - Anode, salt bridge

d - Salt bridge, cathode

18- For a spontaneous process at constant temperature and pressure, there must be a............. of the Gibbs free energy, (ΔG)_{P, T}.

a - lowering

b - increasing

c – matching to zero

d – None of them

19- A vapour must be more disordered and so have higher entropy than a liquid, so the entropy of vaporization is..............

a – negative b- positive c- zero d- equal to heat change

20- mThe correct relationship between free energy change of a reaction and the corresponding equilibrium constant K is..............

a - -△G = RT lnK

b - △G⁰ = RT lnK

c - -△G⁰ = RT lnK

d - △G = RT lnK

26- Which of the following complexes shows zero crystal field stabilization energy?

a- [Co(H₂O)₆]³⁺

b- [Fe(H₂O)₆]³⁺

c- [Co(H₂O)₆]²⁺

d- [Mn(H₂O)₆]³⁺

27- How many unpaired electrons are present in [CoF₆]^3- complex?

a- 4

b- zero

c- 2

d- 3

28- Which of the following d orbitals take part in the octahedral complex with d²sp³ hybridisation?

a- dxy, dyz

b- dxz, dx²−y²

c- dx²−y², dz²

d- dz², dxz

29- Find the molecule having the highest bond order

a- O₂⁺

b- O₂^–

c- O₂^2-

d- O₂

30- Which of the following is true for the formation of stable bonds according to valence bond theory?

a- Greater overlapping between atomic orbitals

b- Close proximity between two atoms

c- Pairing of electrons having opposite spins

d- All of the above

Organic chemistry

31- Which of the following does not come under the organic addition reaction

a- Halogenation

b- Hydrohalogenation

c- Hydration

d -Dehydration

32- Which of the following organic compound with molecular formula C3H6 Cl2 exhibits only one signal in the IH NMR spectrum

a- 1, 2-dichloropropane

b- 1, 1-dichloropropane

c- 2, 2-dichloropropane

d- 1, 3-dichloropropane

33-Which of the following organic compound is formed when aniline reacts with acetaldehyde?

a- Diazonium salt

b- Immine

c- Schiff’s base

d- Carbylamine

34- Which of the following will be the product ‘a’ in the given reation

a- Chlorobenzene

b- Benzene

c- Benzene diazonium chloride

d- Enolate form

35- The IUPAC name for (CH3)2CHCH(CH3)CH2CH=CH2 is

a- 4,5-dimethyl-1-hexene

b- 4,5,5-trimethyl-1-pentene

c- 2,3-dimethyl-5-hexene

d- 4-methyl-4-isopropyl-1-butene

36- Which of the following is the simplest member of organic compounds?

a-Formic acid

b- Formaldehyde

c- Methane

d- Methanol

37- Which of the following is a classification of Organic compounds?

a- alicyclic compounds and acyclic compounds

b- Cyclic compounds and alicyclic compounds

c- Open chain compounds and acyclic compounds

d- Open chain compounds and linear chain compounds

38- Which of the following is yielded when Ethylene glycol is treated with phosphorus tri-iodide?

a- ethylene di-iodide

b- ethylene

c- ethane

d- ethyl iodide

39-Hydrocarbons are organic compounds with element __________

a- Both hydrogen and carbon

b- Carbon

c- Hydrogen

d- Oxygen

40-Which of the following bond is made up of a large number of organic compounds?

a- Metallic bond

b- Dipolar bond

c- Ionic bond

d- Covalent bond

Biochemistry

41- Deterioration of food (rancidity ) is due to presence of :

a- Cholesterol

b- Vitamin E

c- Peroxidation of lipids

d- Phenolic compounds

42- Molecular formula of cholesterol is

a- C27H45OH

b- C29H47OH

c- C29H47OH2

d- C23H41OH

43- Free fatty acids are transported in the blood

a- Combined with albumin

b- Combined with fatty acid binding protein

c- Combined with β- lipoprotein

d- In unbound free salts

44-Arabinose monosaccharide from

a- Aldopentoses. b- Ketopentoses. c- Aldohexoses d- ketohexoses

45-The Uronic acids are

a- Sugar derivatives produced by oxidation of carbonyl group to carboxylic group.

b- Sugar derivatives produced by oxidation of last hydroxyl group to carboxylic group.

c- Sugar derivatives produced by oxidation of carbonyl and last hydroxyl groups to carboxylic groups.

d- Sugar derivatives produced by reduction of carbonyl group to carboxylic group.

46- Branching enzyme one from

a- enzymes of Glycogenesis pathway.

b- enzymes of Gluconeogenesis pathway.

c- enzymes of Glycogenolysis pathway.

d- enzymes of Glycolysis pathway.

47-How many steps of urea cycle occur in liver mitochondria and cytosol?

a-3 steps in mitochondria and 3steps in cytosol.

b-3 steps in mitochondria and 2steps in cytosol.

c-2 steps in mitochondria and 3steps in cytosol.

d-3 steps in mitochondria and 2steps in cytosol.

48-We are incapable of synthesizing some of the standard amino acids.

a- 10 amino acids. b- 5 amino acids c- 20 amino acids d- 7 amino acids

49-DNA contain nitrogenous bases are

a-Adenine,Guanine,Cytosine and Uracil.

b-Adenine,Guanine,Thymine and Cytosine.

c-Uracil, Guanine,Thymine and Cytosine.

d-Cytosine,Uracil, Thymine and Adenine.

50-Which is RNA contain the anticodon arm?

a-mRNA.

b-tRNA.

c-rRNA.

d- mRNA and rRNA.