Year Sem Exam 2010

8/3/2019 Year Sem Exam 2010

1/15

Year 10 Science

Semester Two Examination - 2010

TIME ALLOWED15 MINUTES READING

1 HOUR AND 15 MINUTES WRITING

Instructions to candidates:

1) Do not write or mark the examination booklet in any way during reading time.

2) Please check that, aside from this test booklet, you also have a double sided multiple-choice answer and datasheet.

3) There are 13 pages in this booklet including this one. Please check to ensure that this is so.

4) Note that the time allocated for the examination is 75 minutes and that 75 marks have been allocated: this shouldgive you a guide as to how much time you should spend on each section.

5) There are 4 sections in this booklet: multiple choice, true/false, definitions and extended questions.

6) Graphic calculators must not be used. Dictionaries must not be used. Scientific calculators can be used.

7) If you finish early please do not waste your time: you only get examination time once so it should not be wasted.Check your work thoroughly: calculations, grammar and spelling. Re-read the questions and check your answersto ensure that you have actually answered the questions asked.

8) When the signal to write is given fill in your name, form and teacher details on this booklet (below) and on themultiple choice answer sheet before you begin answering any questions.

9) All answers in this booklet must be completed in pen.

Name................................................................

Form.................................................................

Teacher............................................................


2/15

MHS Year 10 Science Semester Two Examination - 2010

2

Section 1: Multiple ChoiceWrite your selections on the answer sheet supplied. Please place the answer sheet in thisbooklet when you hand in this exam. This section is worth 25 marks.

1. Which of the following equations cannotbe correctly completed by replacing X with 2H2O?

a) C3H8(g) +5O2(g) 3CO2(g) + X

b) 2Na(s) +X 2NaOH(aq) +H2(g)

c) H2SO4(aq) + 2NaOH(aq) Na2SO4(aq) +X

d) X 2H2(g) +O2(g)

2. Crude oil found in deposits across the middle east can best be described as:a) a hydrocarbon compound.b) a mixture of hydrocarbon solids, liquids and gases.

c) an emulsion of insoluble solid hydrocarbons in water.d) A mixture of alkenes.

3. Which of the following exists as a diatomic element?a) heliumb) carbon dioxidec) carbond) chlorine

4. Which of the following does not accurately describe CO32-

a) It is a polyatomic moleculeb) It is an anionc) It is known as the carbonate ion

d) It contains covalent bonds between the carbon atom and the oxygen atoms

5. Which of the following equations correctly shows the reaction between hydrochloric acid and sodium carbonate?

a) 2HCl + Na(CO3)22 NaCl + 2H2O + 2CO2

b) HCl + NaCO3 NaCl + H2O + CO2

c) 2HCl + Na2CO3 2NaCl + H2O + CO2

d) 2H2Cl + 2Na(CO)2 2NaCl + 2H2 + 2CO2

6. The products of the reaction between sulfuric acid (H2SO4) and zinc are:a) zinc sulfate and water.b) sulfur, dioxide and zinc oxide.c) zinc hydroxide and sulfur.d) zinc sulfate and hydrogen.

7. The molea) is a measure of concentration of a substanceb) is a measure of the amount of substancec) is representative of 6.02 x 10

-23atoms

d) has the unit molar

8. The atoms in the compound calcium carbonate are held together bya) Ionic bonding onlyb) Ionic and covalent bondingc) Covalent bonding onlyd) Ionic, metallic and covalent bonding


3/15


3

9. The flow of charge per second in a circuit is measured using a) an ammeter connected in parallel.b) an ammeter connected in series.c) a voltmeter connected in parallel.d) a voltmeter connected in series.

10.An electric kettle has a resistance of 24 while using the 240 V power supply. What is the current that flowsthrough this appliance?a) 5760 Ab) 264 Ac) 10 Ad) 0.1A

11.Three 10 resistors can be connected to give a total resistance of less than 4 by connecting them in whichway?

a) c)

b) d)

12.10mA of current passes through the battery in the circuit shown below. What are the readings on the ammetersA1, A2 and A3 respectively?

a) 5 mA, 5 mA, 10 mAb) 10 mA, 10 mA, 5 mAc) 10 mA, 10 mA, 0 mA

d) 5 mA, 5 mA, 5 mA

13.The SI unit for capacitance is:a) Coulombsb) Amperesc) Farads

d) Ohms

14.A 20 resistor in parallel with a 40 resistor would have a combined resistance of:

a) 60 .

b) 30 .

c) 0.075 .

d) 13.3.


4/15


4

15.The graph below shows the relationship between voltage (x) and current (y) across a resistor.

y

x4 8 12 16 20 24

2

4

6

The resistance of this resistor is closest to:

a) 8 .

b) 4 .

c) 0.25 .

d) 0.04 .

16.Which of the following statements is correct for the circuit shown.

a) V4 + V3 = V1 + V2b) V4 = V1+ V2+ V3c) V2= V1 + V3d) V4 = V2 + V3

17. In the circuit drawn below, the value of the second resistor (X) is:

a) 50 .

b) 100 .

c) 200 .d) 6 .

18.Which of the following represents a functional adaptation of an organism?a) Baby mammals producing the enzyme lactase so they can digest sugars in their mothers milk.b) Butterfly fish have fake eyespots near its tail.

c) North American bears hibernate in winter.d) None of the above.

Current(A)

Voltage(V)


5/15


5

19.Which of the following represents a behavioural adaptation of an organism?a) Chameleons change their colour depending on the background.b) Cheetahs hunt by approaching their prey slowly and silently.c) Humans with one copy of the sickle-cell anaemia gene have a resistance to malaria.d) None of the above.

20.Which of the following ideas is most closely associated with Jean Baptiste Lamarcks theory? a) sudden speciation followed by long periods of stability

b) evolution by natural selection

c) evolution by inheritance of acquired characteristics

d) evolution as a result of a change in the frequency of certain genes in a population

21.Alfred Russell Wallace and Charles Darwin were the first to:a) explain the source of the natural variation occurring within a species

b) challenge the idea of the fixity of species

c) suggest that characteristics acquired during a lifetime could be passed on to offspring.

d) propose the idea of natural selection to explain how organisms evolve

22.Wombats and koalas are different but related species of Australian marsupial. They represent an example of:a) divergent evolution.b) convergent evolution.c) parallel evolution.d) mutation.

23.Dolphins and sharks share a common environment, but are from different classifications of animals. Sharks arecold-blooded fish, but dolphins are warm-blooded mammals. This is an example of:a) divergent evolution.

b) convergent evolution.c) parallel evolution.d) mutation.

24.A cattle farmer introduces a special breeding program in an effort to produce cows with the most desirablecharacteristics. The farmer only selects those cows for breeding that produce a lot of muscle and little fat, andthat convert feed into muscle efficiently so that growth is rapid. Such a breeding program is an example of:a) natural selection.b) Darwin's theory of 'survival of the fittest'.c) mutation.d) artificial selection.

25. In humans there are a number of vestigial structures, such as the appendix and muscles behind the ears. Theseserve no function in humans, but do resemble functional structures in other species. Which statement below bestdescribes why these structures still remain?a) The structures remain because one day humans might need these structures again.b) The structures remain because humans dont need to adapt to environments.c) There is an advantage in having these structures, so there has been a selective pressure to evolve with

them.d) There is no real disadvantage in having these structures, so there has not been selective pressure to evolve

without them.


6/15


6

Section 2: True and FalseIndicate whether the following statements are true or false by placing 'T' for true or 'F' for falsein the boxes following each statement. This section is worth 5 marks.

1. Compounds collectively known as organiccompounds all contain hydrogenatoms.

2. The unit for relative molecular mass is mol.

3. Using the right hand grip rule, the thumb indicates the direction of the magneticfield.

4. LEDs must be placed in the correct orientation for current to flow.

5. Genetic variation does not exist within disease causing bacteria.

Section 3: DefinitionsGive a term to fit each of the following definitions. This section is worth 5 marks.

1. The family of hydrocarbons in which thecompounds contain only single covalent bonds.

2. The term for reactions that result in 2 or moreproducts forming from a single reactant.

3. The SI unit of resistance.

4. Represented by the silver or gold bands onresistors

5. The genetic process that causes variation ingenes.


7/15


7

Section 4: Extended QuestionsGive detailed answers to each question in the spaces provided. Answers that do not show allrequired mathematical working will not obtain full marks. This section is worth 40 marks.

1. Guido performs a chemical reaction in the science lab. Two colourless solutions are mixed, lead nitrate solutionand potassium iodide solution. The result of the reaction is bright yellow and opaque. The teacher says to Guidothat a precipitationreaction has been performed and that he could collect the precipitate.

a) What does the word precipitatemean in this context?

b) How might Guido collect the lead iodide precipitate?

(1 + 1 = 2 marks)

2. Consider the following word equation:

solutionnitratecopper(II)+silversolutionnitratesilver+copper

a) List the i) reactants and ii) the products?

i) ii)

b) Name the type of reaction represented by the above equation?

c) Using the valency table on the data sheet, what are the chemical formulae for:

i. silver nitrate

ii. Copper(II) nitrate

d) Write a balanced equation (including states) for this reaction.

(1/2 + 1/2 + 1 + 2 = 4 marks)


8/15


8

3. Fructose is a simple sugar and an isomer of Glucose.

The Molecular formula of fructose is C6H12O6.

a. What type of bonding exists between the atoms in the fructose molecule?

b. What is the Relative Molecular Mass of fructose?

c. What percentage of the molecular mass of fructose is made up of carbon?

d. How many mol of fructose is there in 25 grams of fructose?

e. What mass of fructose is there in 0.30mol. of fructose?

(1 + 1 + 2 + 1 + 1 = 6 marks)


9/15


9

4. Propane and octane are two hydrocarbon compounds derived from crude oil.

a) State the formula of octane.

b) Which of the two compounds above has the lowest boiling point?

c) Which of the two compounds above is a liquid at room temperature?

d) What are the two products of the complete combustion of propane in oxygen?

(1 + 0.5 + 0.5 + 1 = 3 marks)

5. The following questions refer to the circuit diagram below.

a) Calculate the total resistance of the circuit.

b) Calculate the current flowing through point A

Ac) (Circle the correct response.) The current at point G is:

Greater than at point A The same as at point A Less than at point A

d) What is the potential difference (voltage drop) across:

CD:V

DG: V

DE:V


10/15


10

The circuit is now modified by adding a new path

e) What is the total resistance of the circuit now?

f) Calculate the new current flowing through point A

A

g) What is the potential difference (voltage drop) now across:

CD:V

GH: V

DG:V

h) Calculate the current through each branch of the parallel part of the circuit:

Current through E:

Current through J:

(2 + 2 + 0.5 + 2.5 + 3 + 2 + 2 + 2 = 16 marks)


11/15


11

6. The diagram below shows some of the different species of finch found by Charles Darwin on the GalapagosIslands and a possible evolutionary history of these species. (The Galapagos Islands are geologically veryyoung, being made of a number of active volcanoes, over a thousand miles from the mainland South Americancontinent.)

a) Explain what it means for the woodpecker finch and the warbler finch to be two different species.

b) Of the different species shown in the diagram, which do you think is the oldest species and why?


12/15


12

c) How are these different species of finch adapted to their respective environments? Give an example.

(2 + 1 + 2 = 5 marks)7. The following is an excerpt from an article about the rise of antibiotic resistance in bacteria.

The first antibiotics were prescribed in the late 1930s, beginning a great era in discovery, developmentand prescription. Bacterial infection, as a cause of death, plummeted. Between 1944 and 1972 humanlife expectancy jumped by eight years - an increase largely credited to the introduction of antibiotics.Many experts were confident the tide had turned in the war against bacterial infections. Indeed, in 1969,the then US Surgeon General, William Stewart, boldly told the US Congress it was time to "close thebooks on infectious diseases."

Some experts, however, were uncomfortable with these predictions including Alexander Fleming:

"The greatest possibility of evil in self-medication is the use of too small doses so that instead of clearing up

infection the microbes are educated to resist penicillin and a host of penicillin-fast organisms is bred out which can

be passed to other individuals and from them to others until they reach someone who gets a septicaemia or

pneumonia which penicillin cannot save."

(New York Times June 26, 1945)

By the 1950s, when antibiotics were still new, there was ample evidence of the emergence of resistance.In fact, within four years of penicillin being introduced onto the market, resistant infections were beingreported.

source: http://www.abc.net.au/science/slab/antibiotics/history.htm

The diagram below shows Staphylococcus aureus(Golden Staff), one of the most dangerous causes of bacterialinfections.

A pair of Staphylococcus aureus have gone through 2 cell divisions, producing a pair of

tetrads. Cell division in this and other bacteria can occur every 20 to 30 minutes.

source: http://www.cellsalive.com/gallery.htm


13/15


13

a) Explain how a population of bacteria develops resistance to antibiotics.

b) Give two reasons why this evolution in bacteria occurs at a much more rapid rate than is noticeable in mostother species.

(2+2=4 MARKS)

END OF PAPER


14/15


14

Answers

Section 11 a 2 b 3 d 4 a 5 c 6 d 7 b 8 b9 b 10 c 11 d 12 a 13 c 14 d 15 b 16 d17 c 18 a 19 b 20 c 21 d 22 a 23 b 24 d25 d

Section 21 2 3 4 5T F F T F

Section 3

1. Alkanes 2. decomposition 3. Ohms4. (resistor)

tolerance5. Mutation

Section 4 (Only half marks if no calculations are shown!)

1. a) An insoluble solid formed when 2 aqueous solutions react (1 mark)b) Filter the mixture through filter paper (1 mark)

2. a) i) Copper, silver nitrate ii) Silver, copper(II) nitrate (1/2 mark)b) Displacement reaction (1/2 mark)c) AgNO3, Cu(NO3)2 (1/2 mark each = 1 mark))d) Cu(S) + 2AgNO3(aq) 2Ag(s) +Cu(NO3)2(aq) (1 mark all species + 1/2 mark balanced + 1/2

mark states)=2 marks

3. a) covalent. (1 mark)b) 180 (amu) (1 mark)c) 6 x 12x 100/180 = 40% (2 marks)d) 25/180 = 0.1389mol. (2 marks)

e) 0.3 x 180 = 54 grams (1 mark)4. a) C8H18 (1 mark)

b) Propane (1/2 mark)c) Octane is a liquid. (1/2 mark)d) Carbon dioxide & water are the products of combustion. (1 mark)

5. a) 500 + 150 + 400 = 1050 (2 marks)b) 9/1050 = 0.0086A (2 marks)c) The same as point A (1/2 mark)d) CD: 500 x 0.0086 = 4.29 V, DG: 150 x 0.0086 = 1.29 V, DE: zero (1+1+0.5= 2.5 marks)e) 1/Rpara=1/150 + 1/(100+200)= 3/300 /Rpara =100,Rtot =500+100+400 =1000(3 marks)f) I = V/R = 9/1000 = 0.009 A (2 marks)g) CD: 0.009 x 500 = 4.5V, GH: 0.009 x 400 = 3.6V DG: 9 (4.5 + 3.6) = 0.9V (2 marks)

h) Current thru E: I = V/R = 0.9/150 = 0.006A, Thru J: 0.9/300 = 0.003 A (or 0.009 0.006 =0.003A) (2 marks)

6. a) These birds are different species because they have developed enough geneticvariations (1) that they would be unable to successfully interbreed and producefertile offspring (1).

b) The large ground finch would be the oldest finch (0.5) as the other species allshow evidence of having descended from that species (0.5).

c) The species have different beak structures appropriate for finding food in differentenvironments (1).For example the woodpecker finch has a long, sharp beak that allows it to boreholes in trees and remove insects (1).

d) It would be very unlikely that the same species would be found anywhere else, dueto the geographic isolation of the Galapagos Islands (1). It is possible though, that ina similar environment elsewhere, similar species have evolved in parallel (1).


15/15


15

7. a) Within the species, there will be some bacteria that are naturally immune to or lessaffected by a particular antibiotic (1).Over time, the proportion of these resistant bacteria in the population will increase,as the less resistant bacteria are more likely to be killed off (1).

b) Two reasonable answers (one mark each) such as:

Bacteria have a very rapid reproductive cycle (measured in minutes rather thanmonths or years).

The population is under a great deal of pressure from antibiotics.

The large numbers in a bacterial population mean that the chance of beneficialvariation occurring in a bacterium is higher.

The genetic changes required for resistance in antibiotics arent as complex asthose required for larger scale evolutionary changes in multi-cellular organisms.

Documents

Year Sem Exam 2010