Read carefully the following instructions:

Student Training Course for the 6

International Junior Science Olympiad

Training Programme

Screening Test – Phase I

May 23, 2009

Read carefully the following instructions:

1. The time available is 2 hours.

2. Check that you have a complete set of the test questions and the answer sheet. 3. Write your name and school name on the examination paper and answer sheet. 4. There are 55 multiple-choice questions and 6 short questions in total.

5. All multiple-choice questions will be in 4-option format. 6. Point rules:

Full mark: 85 points Multiple Choice (55 points) - Correct answer: +1.0 points - Wrong answer: -0.5 points - No answer: 0.0 point Short Questions (30 points) - 5 points each

7. You should mark the answers on the answer sheet using. Answers written in the question book will not be marked.

8. This examination paper must be returned together with your answer sheet.

Candidate Name.:

PART A: Multiple Choice (Correct: +1.0 points; Wrong: -0.5 points; No answer: 0.0 points)

1. Which of the following compounds has the smallest bond angle? A. CH4

B. NH3 C. BH3 D. H2O

2. Arrange the species in the order of increasing N-H-N bond angle. A. NH4+ < NH3 < NH2

-B. NH3 < NH4+ < NH2 -C. NH2- < NH3 < NH4+ D. NH4+ < NH2- < NH3

3. Shown below are the isotopic masses and the natural abundances of the isotopes of iron. Calculate iron’s atomic mass.

Isotopes Isotopic Masses Natural Abundance (%)

54 Fe 53.9396 5.845 56 Fe 55.9349 91.754 57 Fe 56.9354 2.119 58 Fe 57.9333 0.282 A. 55.845 B. 56.025 C. 56.186 D. 56.435

4. The atomic numbers of elements X and Y are 20 and 35, respectively. X and Y form a stable compound with a chemical formula of:

A. XY B. XY2 C. X2Y D. XY3

5. Show below are the atomic numbers of elements P, Q, R, and S. Which element has the highest melting point?

Element P Q R S Atomic number 5 14 35 37 A. P B. Q C. R D. S

(Note: In this question, P ≠ phosphorus and S ≠ sulphur)

6. Show below are the atomic numbers of elements W, X, Y, and Z. Which element has the largest atomic radius?

Element W X Y Z Atomic number 17 18 19 20 A. W B. X C. Y D. Z

7. Show below is the chemical structure of caffeine. How many σ bonds does this compound have? N C N C C C N CH N O O CH₃ H₃C CH₃ A. 11 B. 21 C. 25 D. 29

8. Refer to the chemical structure of caffeine that shown in the previous question. How many atoms in a caffeine molecule are sp3 hybridized?

A. 6 B. 8 C. 11 D. 13

9. Which of the following statements about the chemical structure shown below is/are correct?

C C

H

C

C

C

H

H

H

H

H

(m)

(n)

(o)

(p)

(i) The C-H bond marked with (n) is longest (ii) The C-H bond marked with (m) is shortest

(iii) The bond angle marked with (p) is smaller than 120o

(iv) The 8 atoms that are underlined are always on the same plane. A. (i) and (iv) only

B. (ii) and (iii) only C. (ii) and (iv) only D. (iv) only

10. An element Z forms a nonpolar compound with hydrogen. What is the atomic number of Z? A. 4

B. 5 C. 7 D. 8

11. Which of the following species has the shortest bond length? A. N2

B. O2 C. F2 D. Cl2

12. How many pairs of lone-pair electrons are present in HNO3? A. 5

B. 6 C. 7 D. 8

13. The H-N-N bond angle in N2H2 is closest to A. 109º

B. 120º C. 150º D. 180º

14. Calculate the value of p in the diagram below. (The values next to the liquid levels indicate the heights of the levels as measured by the ruler with an unit of mm.) The densities of oil, water and mercury are given below. Also given: p0 = 9 mmHg.

Liquid Density (g/cm3) Oil 0.7 Water 1.0 Mercury 13.6 A. 3 mmHg B. 8 mmHg C. 10 mmHg D. 15 mmHg

15. A student wanted to find out the value of the Universal Gas Constant, R. He used a box to contain 0.01 moles of gas at 300 K. The volume of the box was 0.45 ft3 (cubic-feet) and found that the gas pressure was 2 atm. What is the value of R? Given: pV = nRT.

A. 7.5 x 10–6 ft3⋅atm⋅K–1⋅mol–1 B. 0.30 ft3⋅atm⋅K–1⋅mol–1 C. 3.3 ft3⋅atm⋅K–1⋅mol–1 D. 1.3 x 105 ft3⋅atm⋅K–1⋅mol–1

16. A rigid box (i.e., the volume of the box cannot be changed) contains a sample of ozone gas (O3). When the temperature is 300 K, the pressure of the gas is 2 atm. The box is then heated up to 600 K and kept at this temperature. After one day, all the ozone gas is converted to oxygen gas (O2). What is the pressure of the oxygen gas at 600 K? (Hint: you need to write down the balanced equation for the change of ozone to oxygen.)

O3 → O2 300 K 2 atm 600 K ? atm A. 0.66 atm B. 1.5 atm C. 2.6 atm D. 6.0 atm

17. The following gases are stored in three separate containers at the conditions shown below. These containers are connected and the gases are allowed to mix with each other until the content is homogeneous. The resulting “big” container is kept at 300 K. What is the total pressure of the gas mixture?

He: 3 atm, 4 L, 400K; O2: 6 atm, 2 L, 200K; N2: 2 atm, 2 L, 600K A. 0.5 atm

B. 3.0 atm C. 4.0 atm D. 6.0 atm

18. What is the pH value of a buffer solution that contains 0.1M in acetic acid (HA) and 0.1M sodium acetate (NaA)?

(Given: Ka for acetic acid is 1.75 x 10-5)

A. 1 B. 3.76 C. 4.76 D. 0.1

HA (aq) + H2O (l) H3O+ (aq) + A- (aq)

[

][ ]

[ ]

HA

A

O

H

K

=

19. What is the molarity of water? Given: density of water 1gram/mL) A. 5.55M

B. 0.555M C. 0.0555M D. 55.5M

20. A solid sample contains certain amount of NaOH. During the titration, it was found that 2 gram of sample needed 20mL 0.5M HCl to neutralize the solution. Calculate the percentage of NaOH in the sample.

(Given: atomic weight of Na:23, O:16 and H:1) A. 40%

B. 20% C. 10% D. 5%

21. What is the standard deviation of the following set of data: {3, 4, -10, -20}? A. 9.25 B. -3 C. -5.75 D. 9.91

22. What is the probability of choosing a card from a deck: the card is an odd number and a red card and an ace?

A. 0 B. 1 26 C. 1 13 D. 1 52

23. For the growth of a certain plant, one uses a graph to record the data where y-axis shows

( )

3

log h where h is the height of the plant while x-axis shows log t where t is the time ₃

( )

24. By referring to the following figures:

what is the height (h) of the cone if the volume of the cone is equal to the volume of the sphere of radius r?

A. h=4r B. h=r C. 4

r

h= D. h=16r

25. What is the slope of the straight line of equation: 3x+7y+ =1 0? A. 3 7 B. 3 7 − C. 7 D. 1 7 −

26. A cart of 30 kg with initial speed 1 m/s stops after sliding for 3 s. What is the friction acting on it?

A. 5 N B. 10 N C. 15 N D. 20 N

27. A ball initially at rest is placed on a wedge with a smooth inclined surface as shown in the diagram. It travels a distance s and reaches the ground with speed v. Find v.

A. v=2gscosθ B. v=2gssinθ C. v= 2gscosθ D. v= 2gssinθ

28. A box of mass m is attached to a ceiling by a massless rope. A force of magnitude F is applied horizontally to the box so that the rope makes an angle 30o with the vertical as shown below. If the box is in equilibrium, find the force F.

A. F = 2mg B. F =mg/ 3 C. F =mg/ 2 D. F = 3mg

29. A rod of length 10 m is balanced on a fulcrum with a 2-kg box on one end of the rod and a 4-kg box on the other end as shown in the diagram. How far is the location of the fulcrum from the center of the rod? You may neglect the mass of the rod.

A. 1.25 m B. 2.34 m C. 1.67 m D. 3.33 m

30. 0.3 litre of pure water (density = 1 kg/litre) is mixed with 1 litre of sea water (density = 1.022 kg/litre). What is the density of the mixture?

A. 0.912 kg/litre B. 1.017 kg/litre C. 1.302 kg/litre D. 1.122 kg/litre 31. When a comet is very far from the sun, which part(s) of it can still exist?

A. Tail B. Coma and tail C. Nucleus and tail D. Nucleus 32. What are the three basic types of galaxy?

A. Spiral, Elliptical, Irregular B. Spherical, Elliptical, Irregular C. Spiral, Barred, Elliptical D. Barred, Elliptical, Irregular

33. If the radius of the Earth is decreased by half, while other things remain unchanged, which statement below is correct?

A. The gravitational acceleration on the Earth’s surface also decreases. B. The gravitational acceleration on the Earth’s surface increases. C. The average density of the Earth also decreases.

34. Which statement about the planets in the solar system is correct? A. The planets move in circular orbits around the sun.

B. Jupiter has the highest average density among the planets. C. Venus has a thick atmosphere.

D. The orbital period of Uranus is longer than that of Neptune. 35. A planet in the solar system has the following properties.

I. Its average density is lower than water. II. It has a ring system.

III. One of its satellites has an atmosphere. Which planet is it?

A. Mars B. Jupiter C. Saturn D. Uranus

36. Which of the following is not the component of nucleic acid? A. Organic nitrogenous bases

B. Phosphate C. Ribose D. Steroid

37. Which of the following is not true?

A. The breakdown of starch into glucose requires water. B. Copper is the component of chlorophyll in plants.

C. Cells are only formed from the division of pre-existing cells. D. Virchow proposed that all cells come from cells.

38. Glycogen is different from starch in that A. it consists of branches.

B. it is made from fructose molecules. C. it is soluble in water.

D. the ratio of hydrogen to oxygen is 2:1. 39. Which of the following is not true?

A. Small non-polar molecules can pass through the cell membrane freely. B. Ions need to pass the cell membrane through channels.

C. The hydrophobic tails of the phospholipids of the cell membrane line at the outside of the cell.

D. Smooth endoplasmic reticulum is abundantly found in cells of steroid synthesizing tissues.

40. Respiration occurs on the surfaces of A. cristae in mitochondrion. B. rough endoplasmic reticulum. C. Golgi body.

D. nuclear envelope.

41. The maturation of sperms needs

A. nutrients secreted from Sertoli cells. B. change of Golgi body into acrosome.

C. reducing the number of chromosomes by half. D. hormone oestrogen.

42. Which of the following statements on the developmental stages of human embryo is not correct?

A. Morula contains 32 cells stage.

B. Blastocyst is a hollow ball with a fluid-filled cavity. C. Gastrula contains a two-layered embryo.

D. Notochord, brain and spinal cord are the first organs to develop in the embryo. 43. In giving birth,

i. the myometrium of the uterus contracts to expel the foetus from the uterus. ii. amniotic fluid is released to the vagina as lubricant for the passage of the foetus. iii. the placenta is expelled out before the baby.

A. i, ii B. ii, iii C. i, iii D. i, ii, iii

44. The tail of sperm is formed from A. Golgi body.

B. mitochondrion. C. DNA.

D. centriole.

45. Which of the following statement is true? A. Fertilization occurs in the ovary.

B. The cell division carried out by the primary oocyte is uneven. C. The lining of the uterus will be shedded off if fertilization occurs. D. Hormones from the ovary are secreted by the oocytes.

46. Which of the following is NOT considered as an evidence of evolution? A. Closely related species.

B. Comparative anatomy of homologous structures. C. Convergent development of analogous structures. D. None of the above.

47. The followings are rudimentary structures which functions were lost in the course of evolution except:

A. Eyes of blind cave fish. B. Hind limbs of python. C. Spiracles of grasshopper. D. Caecum in human beings.

48. The fossil with characteristics of both reptiles and birds and considered as an evidence of evolution is

A. Cooksonia. B. Coelacanth. C. Archaeopteryx. D. Nautilus.

49. Which of the following statements regarding the role of mutations in evolution is INCORRECT?

A. Mutations are more frequently encountered than variations.

B. In the majority of cases mutations brought disasters to their bearers. C. Mutations may create a new allele of existing genes.

D. Polyploidy is regarding as a type of mutation. 50. Polyploidy:

I. Results an increase in the amount of genetic material. II. Is more common in animals.

III. Is the result of improper separation of chromosomes during cell divisions. IV. Usually is a result of behavioral Isolation.

V. Usually is a result of gametic isolation. A. Only one of the above statements is true. B. Two of the above statements are true. C. Three of the above statements are true. D. Four of the above statements are true.

51. Protozoans living in stomach of herbivores mainly assist their host by helping the digestion of A. protein.

B. glycerol. C. lipid. D. cellulose.

52. Which of the following statements regarding sexual parasitism is FALSE?

A. It refers to the phenomenon that individuals of a particular sex of a particular species being parasitic on individuals of the opposite sex.

B. Sexual parasitism could be observed in deep sea angler fish.

C. Sexual parasitism ensures the chance of mating for organisms present in extremely low densities.

D. None of the above.

53. Which of the followings is a commensal organism? A. Tapeworm.

B. Remora.

C. Caterpillar fungi. D. Brown-headed cowbird.

54. Which of the following examples is not a cleaning symbiosis? A. The cleaner shrimp and the coral reef fish.

B. The anemone and the anemonefish. C. The cleaner fish and other coral reef fish. D. The oxpecker and the zebra.

55. Hyperparsitism is referred to as:

A. The parasitism on the original host with a new generation of parasitic larvae.

B. The parasitism on a parasitic organism that is already associated with the original host. C. The parasitism on a parasitic organism which became free living.

D. Double parasitism of two parasites on the common host.

PART B: Short Question (5 points each)

1. Calculate the volume of hydrogen gas produced if 5.00 g of calcium metal was reacted with water. Assume the gas volume was measured at 25oC and 1 atm. (Atomic mass of Ca = 40.078)

2. Arrange H2, F2 and HF according to increasing order of their boiling points. Provide explanation for your answer.

3. The equation of a parabola with vertex at point

(

)

2

4 8 7

y= x − + . x

(a) Find the value of y whenx=0. (b) Determine the values of α and β. (c) What is the value of x when y=0.

4. A particle of mass m = 1 kg is attached to a ceiling by a string as shown in the diagram. If the particle moves in a horizontal circle of radius R = 1 m with constant speed v = 3 m/s, what is the tension T in the string? (Take g = 9.8 m/s2)

5. Define the terms "variation" and "mutation" and briefly discuss on the roles they play in the process of evolution.

6. Give the major differences in cellular organization between prokaryotic and eukaryotic cells.