8th Grade Science Benchmark Exam #2 2010-2011
(Reference Sheet on Page 10)
1. Which list contains only elements?
A steel, bronze, brass
B ammonia, fluoride, nitrate
C carbon, helium, nitrogen
D quartz, silicon, phosphates
2. What is the name of the atom represented by the letter “C” in the diagram of a glucose molecule shown below?
A Copper
B Calcium
C Chromium
D Carbon
3. What do the elements argon (Ar), neon (Ne), helium (He), and radon (Rn) have in common?
A They are noble (inert) gases.
B They are liquids.
C They have the same thermal conductivity.
D They have the same number of protons.
4. In the table above, the elements in section 1, the white section, are:
A metals
B reactive nonmetals
C inert gases
D semimetals
5. Which list contains the elements that are most abundant in all living organisms?
A Carbon, Chlorine, Helium, Iron, Lead, Hydrogen
B Hydrogen, Oxygen, Sodium, Carbon, Uranium, Gold
C Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, Sulfur
D Iron, Nickel, Chlorine, Sodium, Chlorophyll, Water
6. Use the periodic table (on page 9) to answer this question. Which list of elements is most likely to have similar chemical and physical properties to Calcium (Ca)?
A K, Mg, Sc, Y
B Be, Mg, Ba, Ra
C K, Ti, As, Kr
D Cr, C, Cl, Cf
7. Lithium has atomic number 3. Every atom of lithium contains:
A 3 protons.
B 3 neutrons.
C 3 electrons.
D 3 total particles.
8. Which of the following compounds is most likely to be part of living organisms?
A C6H12O6
B BF3
C MoCl2
D CsI
9. The model in the picture below represents:
A an element.
B a compound.
C a mixture.
D air.
10. Iron oxide (rust) is a compound of iron and oxygen. Which is true about the physical and chemical properties of iron oxide (rust):
A Iron oxide has the same physical properties as iron and oxygen.
B Iron oxide has the same chemical properties as iron and oxygen.
C Iron oxide has a mixture of the physical and chemical properties of iron and oxygen.
D Iron oxide has different physical and chemical properties than iron and oxygen..
11. When vinegar and baking soda react, the temperature will drop. This means that;
A energy is released in the chemical reaction.
B energy is absorbed in the chemical reaction.
C energy is destroyed in the chemical reaction.
D a change in temperature has nothing to do with energy.
12. The picture below shows how atoms are arranged in a substance. The substance is a:
A polymer.
B liquid.
C plastic.
D crystal.
13. The table below shows the pH of 4 body fluids.
This data indicate that Bile is:
A very acidic
B very basic
C slightly basic
D negatively charged
14. According to the table below, which substance is the most acidic?
A baking soda
B drain cleaner
C milk
D rainwater
15. The carbonic acid (H2CO3) used in soft drinks breaks down to form water (H2O) and carbon dioxide (CO2). Which chemical reaction shows this process?
A H2CO3 + H2O à CO2
B H2CO3 + CO2à H2O
C H2CO3à H2O + CO2
D H2O + CO2à H2CO3
16. Krishna measured the mass of a sealed beaker of ice chips, and then allowed the chips to melt. How will the mass of the resulting water compare to the mass of the ice chips?
A The mass will be greater than the mass of the ice chips.
B The mass will be less than the mass of the ice chips.
C The mass will be the same as the mass of the ice chips.
D The mass cannot be determined.
17. Lucy measured the mass of a candle, and then lit it. She measured the mass of the candle again after letting it burn for 10 minutes. She found the mass of the candle afterward to be less than the original mass. This is most likely because:
A some mass escaped as smoke and soot.
B burning destroys mass.
C heat generally causes a loss of mass during reactions.
D wax has less mass when it melts.
18. Where does the heat and light in a candle come from?
A atoms of wax being destroyed
B energy released by chemical reactions
C atoms of smoke being produced
D the match that lit the candle
19. Mila burned a thin, silvery strip of magnesium metal. This resulted in a white solid powder. How can she tell that the magnesium underwent a chemical change?
A The white powder was soft to the touch.
B Powder formed can be added to water to form a mixture.
C The white powder and magnesium are both chemicals.
D A new product was formed during the reaction.
20. If you took all the atoms out of a chair, what will be left?
A The chair would still be there, but it would weigh less.
B The chair would be exactly the same as it was before.
C A pool of liquid would be left on the floor.
D There would be nothing left of the chair.
21. What characteristic of carbon (C) makes it essential to living organisms?
A Carbon forms crystal structures under certain conditions.
B Carbon can exist as a solid, liquid, or gas.
C Carbon bonds in many ways with itself to form chains.
D Carbon exists in radioactive forms.
22. Which substance does not contain carbon?
A fat
B protein
C carbon dioxide
D water
23. Living things are made of:
A atoms found in the periodic table.
B something not found on the periodic table.
C atoms found on the periodic table plus other substances.
D water only.
24. Which of the pictures below most accurately shows the structure of an atom?
25. Below is the symbol for an oxygen atom. Which element below is an isotope of the oxygen atom?
A
B
C
D
26. A sample of magnesium oxide was massed three times on a balance. The recorded masses were;
2.034g,
2.038g,
2.030g.
What is the MOST likely reason why the three measurements not the same?
A The balance is probably broken.
B There is always some error in measurements.
C The people massing the sample were careless.
D The sample probably changed mass.
27. Which is the correct order of substances from the least movement of molecules to the most movement of molecules?
A water vapor-ice-water
B ice- water vapor-water
C water-water vapor- ice
D ice-water-water vapor
28. Some wax is heated and melts. Which of the following is true of this change?
A the wax molecules change their arrangement
B the wax molecules have less energy
C the wax molecules become something else
D The wax molecules gain more mass
29. Which would be the best test to see if a solid substance was a metal?
A test if it conducts electricity
B test its melting point
C test how it reacts if placed in water
D test its density
30. A 8g piece of plastic has a volume of 10 ml. What will happen if it is placed in water?
A it will float
B it will sink
C it will sink halfway
D there is not enough information to answer the question
Open Ended Question
Pete says that since table salt is made of the element chlorine, which is a poisonous gas, and sodium, which is explosive, it must be a very dangerous substance.
Use your knowledge of chemistry to explain to Pete why table salt is not dangerous even though its components are. Be sure to give other examples to support your conclusion.
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2010-2011 Grade 8 Science Benchmark Exam #2
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2010-2011 Grade 8 Science Benchmark Exam #2
8th Grade Science Benchmark Exam #2 2010-2011
Answer Key
1. C 3f
2. D 3f
3. A 7a
4. A 7a
5. C 6b
6. B 3a
7. A 7b
8. A 6b
9. B 3b
10. D 3b
11. B 5c
12. D 3c
13. C 5e
14. D 5e
15. C 5a
16. C 5b
17. A 5b
18. B 5c
19. D 5a
20. D 3a
21. C 6a
22. D 6c
23. A 6c
24. C 3a
25. C 7b
26. B 9b
27. D 3e
28. A 5d
29 A 7c
30 A 8b
Open Ended
Score / Criteria4- proficient / The student clearly and coherently explains that when elements combine to form compounds the physical and chemical properties of the element can be completely different than those of the compound.
At least one correct example is given and explained. Possibilities include: Hydrogen is explosive, but water is not. Rust cannot be used to build anything strong, but iron can, Carbon dioxide is an invisible gas but pure carbon can have many different forms depending on how it is bonded.
3- basic / The student explains that when elements combine to form compounds the physical and chemical properties of the element can be completely different than those of the compound.
Examples are given but not explained (for example: “water is different than hydrogen”)
2- bb / The student explains that when elements combine to form compounds the physical and chemical properties of the element can be completely different than those of the compound. –but- Examples are missing or incorrect
Or; the student gives an example without explaining the different prperties of elements and compounds
1-fbb / The student is unaware that compounds and elements having different properties. Or just answers that salt is not dangerous.
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2010-2011 Grade 8 Science Benchmark Exam #2