science grade 8 - eduware...do not reproduce science grade 8 1. carbon cannot be decomposed by...

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1st Benchmark for 2008-2009

Science Grade 8

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DIRECTIONS: The items in this test are based on the

North Carolina Standard Course of Study

for Science Grade 8. Proceed with the

test on the next page.

Do not reproduce Science Grade 8

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1. Carbon cannot be decomposed by simple chemical methods into two or more different substances. How is it classified?

A a compound

B an element

C a mixture

D a molecule

2. Which element is a gas at room temperature?

A sodium

B nitrogen

C iron

D carbon

3. What is the name for a substance formed from the chemical union of two or more elements?

A solution

B metalloid

C compound

D colloid

4. What is the most common solvent?

A alcohol

B hydrochloride

C salt water

D water

5. What would increase the solubility of most solids in water?

A increasing the solvent

B increasing temperature

C stirring slowly

D increasing the solute

6. What are elements that conduct heat and electricity called?

A metals

B nonmetals

C metalloids

D noble gases



7. Which property of metal allows it to be hammered into thin sheets?

A conductivity

B ductility

C luster

D malleability

8. Which property of silver is considered a physical property?

A It has a metallic luster.

B It is valuable.

C It has been used to make coins.

D It can combine with chlorine to make silver chloride.

9. Based on the Periodic Table, what two elements have similar chemical properties?

A sodium and potassium

B sodium and oxygen

C silver and phosphorus

D nitrogen and neon

10. Which particles account for most of the mass of the atom?

A protons and neutrons

B protons and electrons

C neutrons and electrons

D neutrons and positrons

11. Which process represents a chemical change?

A burning of paper

B crystallization of sugar

C evaporation of water

D melting of ice

12. All matter has which property?

A color

B luster

C mass

D shape



13.

In the periodic table, what does the number above the symbol for each element represent?

A The number of neutrons in an atom of the element.

B The number of protons in an atom of the element.

C The combined number of protons and neutrons in an atom of the element.

D The combined number of protons and electrons in an atom of the element.



14. Which element is a liquid at room temperature?

A aluminum

B iodine

C mercury

D sodium

15. Consider the following reaction:

2H2(g) + O2(g) → 2H2O(g)

What kind of change is shown?

A physical change

B phase change

C nuclear change

D chemical change

16. After mixing two chemicals in a beaker, a student noticed the beaker became extremely hot. Which best explains the temperature increase?

A an exothermic reaction occurred

B an endothermic reaction occurred

C a precipitation reaction occurred

D a gas producing reaction occurred

17. If a student needs a substance that conducts electricity, has a relatively low density, and is not magnetic, which would the student choose?

A rubber

B plastic

C iron

D aluminum

18. Which illustrates the law of conservation of matter?

A H2 + O2 - H2 O

B Fe + O2 - Fe2 O4

C Mg + 2Cl - MgCl2

D AgNO3 + H2 S - Ag2 S + HNO3

19. Which person would be most affected by exposure to chemicals?

A adult

B infant

C small child

D young adult



20. Which element exhibits both metallic and nonmetallic properties?

A Barium

B Boron

C Krypton

D Potassium

21. A can was filled with crushed ice, sealed, and its mass was determined. The ice was melted by slowly warming the can and its contents. No water vapor escaped and no air entered the can.

After the ice had melted, what is the best prediction of the mass?

A The mass would be the same.

B The mass would be more.

C The mass would be less.

D Impossible to predict without more information.

22. The diagram below represents a portion of a 100-milliliter graduated cylinder.

What is the reading of the meniscus?

A 35.0 mL

B 36.0 mL

C 44.0 mL

D 45.0 mL

23. What happens to a teaspoon of sugar when it is added to a large glass of pure water at room temperature?

A The sugar melts.

B The sugar dissolves.

C The sugar condenses.

D The sugar evaporates.



24. Which of the following is considered to be a synthetic chemical?

25. Recent evidence shows that lakes are being affected by acid rain. What can be a consequence of acid rain?

A an increase in game fish population levels

B the stimulation of a rapid rate of evolution

C the elimination of many species of aquatic life

D an increase in agricultural productivity

26. Which factor would most likely affect the evaporation of surface waters?

A longitude

B type of soil

C type of rocks

D intensity of sunlight

27. What property of water is most important for living organisms?

A It is odorless.

B It does not conduct electricity.

C It is tasteless.

D It is liquid at most temperatures on Earth.

28. What is the major moisture source for most land areas?

A precipitation

B vegetation

C ground water

D stream discharge

29. What process causes water to move upward through the soil?

A capillary action

B permeability

C porosity

D infiltration


A salt

B rubber

C plastic

D sugar


30. Water budget graphs for four cities, A, B, C, and D, are shown below.

Which city would have the driest climate?

A A

B B

C C

D D

31. Points are plotted on the graph below to show the relationship between lake-water pollution and the population density around several small lakes.

What trend does the graph show?

A as population density increases, the lake pollution decreases

B as population density increases, the lake pollution increases

C as population density increases, the lake pollution is unaffected

D the size of the lake determines the population density



32. The graph below shows the stream flow measured during a period of one year.

The stream flow was greatest during which month?

A January

B March

C May

D October

33. What does the hydrosphere mostly consist of?

A solid rock

B liquid water

C gaseous air

D heated magna

34. Why are there greater daily temperature variations on land compared to water?”

A Water has a greater ability to absorb and hold heat than land.

B The oceans form a continuous biome.

C Land areas provide habitats for many organisms.

D The ocean has salt water and many dissolved nutrients.

35. Which process is used in sewage treatment to kill infectious bacteria?

A sedimentation

B chlorination

C filtration

D flotation

36. What surface conditions would cause the greatest infiltration of water into the Earth?

A permeable and saturated soil

B permeable and unsaturated soil

C impermeable and saturated soil

D impermeable and unsaturated soil



37. A diagram of the water cycle is shown below. Letters A through D represent the processes taking place.

Which arrow represents the process of transpiration?

A A

B B

C C

D D

38. Which of the following activities would be more likely to pollute a river?

A allowing beavers to build a dam

B spreading fertilizer near the river

C mowing the grass on the river bank

D fishing from a bridge over the river

39. Why can liquid water store more heat energy than an equal amount of any other naturally occurring substance?

A Liquid water covers 71% of Earth’s surface.

B Liquid water is denser than ice.

C Liquid water has a higher specific heat.

D Liquid water can be changed into a solid or a gas.

40. Why does a raw egg float in saltwater, but sink in freshwater?

A Saltwater is more dense than freshwater.

B The egg absorbs freshwater.

C Saltwater is less dense than freshwater.

D Freshwater has more mass.



41. Which diagram best illustrates the condition of the soil below the water table?

A

B

C

D

42. Why is ocean upwelling important?

A It prevents estuaries from flooding.

B It creates higher tides.

C It decreases the oxygen in the surface waters.

D It moves nutrients from the bottom of the ocean to the top.

43. Dumping raw sewage into a river will lead to the reduction of dissolved oxygen in the water. What will this reduction most likely cause?

A an increase in all fish populations

B a decrease in most aquatic animal populations

C an increase in depth of the water

D a decrease in water temperature

44. A container of water is placed in an open outdoor area so that the evaporation rate can be observed. What weather conditions will cause the water to evaporate fastest?

A cool, humid, and windy

B cool, dry, and calm

C warm, humid, and calm

D warm, dry, and windy



45. Where is most of the water found on Earth?

A the oceans

B the atmosphere

C ponds, rivers and lakes

D polar ice caps

46. Which statement best explains why a cloud is forming as shown in the diagram below?

A Water vapor is condensing.

B Moisture is evaporating.

C Cold air rises and compresses.

D Warm air sinks and expands.

47. Which relationship can be inferred from the data presented in the graph below?

A As sewage waste increases, oxygen content decreases.

B As sewage waste increases, oxygen content increases.

C As oxygen content decreases, carp population decreases.

D As oxygen content decreases, trout population increases.



48. The flowchart below shows part of Earth’s water cycle.

Which process would best complete the flowchart?

A condensation

B deposition

C evaporation

D infiltration

49. Which condition would cause runoff to be greater than infiltration?

A porous soil

B a steep slope

C low rainfall

D plant covered ground

50. Which sequence of atomic numbers represents elements that have similar chemical properties?

A 19, 23, 30, 36

B 9, 16, 33, 50

C 3, 12, 21, 40

D 4, 20, 38, 88



51. Which graph best represents the relationship between water droplet size and the chance of precipitation?

A

B

C

D

52. How does oxygen enter an aquatic system?

A photosynthesis by producers

B respiration by consumers

C photosynthesis by decomposers

D respiration by producers

53. A cube has a volume of 8.0 cm3 and a mass of 21.6 grams. What is the density of the cube expressed in grams per cubic centimeter?

A 2.7

B 27

C 0.27

D 0.027

54. How has the increase in ocean temperatures affected food chains?

A Warm temperatures increase the amount of food consumed by fish.

B Warm temperatures force organisms to swim closer to the surface.

C Warm temperatures force organisms to relocate.

D Warm temperatures increase reproduction.



55. Salt water and freshwater have different densities. Where is saltwater located in an estuary?

A

B

C

D

56. Given the unbalanced equation:

___N2(g) + ___O2(g) → ___N2O5(g)

When the equation is balanced using smallest whole numbers, what will the

A 1

B 2

C 4

D 5

Page 15

End of

Science 8 Exam

coefficient of N2(g) be?

closer to the surface

along the bottom

closer to the shore

in the center

science grade 8 - eduware...do not reproduce science grade 8 1. carbon cannot be decomposed by...

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