8th Grade First Semester Mid-Term Exam

1. What is hydrophobic?

When a molecule repels water

When a molecule is attracted to water

When a molecule is a micelle

When a molecule is ionically bonded

2. What one notices or senses while performing the activity.

Data

Procedure

Observation

Control

3. Identify the property of water that allows a water strider insect to walk on the water.

Surface Tension

Polarity

Capillary Action

Specific Heat

4. What is an atom?

The smallest part of an element that is a basic unit of matter

The unit measure of an element

Elements that make up molecules

Neutrons in the nucleus

5.

Identify the letter of the Hydrologic Cycle given in this question.Letter F is _________________

Streamflow

Groundwater discharge

Snowmelt runoff to streams

Water storage in oceans

Water storage in the atmosphere

Condensation

Evaporation

Sublimation

Evapotranspiration

Surface Runoff

Precipitation

Water storage in ice and snow

Infiltration

Groundwater storage

Spring

Freshwater storage

6. Celery test: What property of water does the celery test model?

Capillary Action

Polarity

Surface Tension

Specific Heat

7. Floating Paper Clip:Why does adding liquid detergent to the water change how the paper clip floats?

It breaks the polarity and therefore the surface tension

Liquid detergent is not soluble

It changes the pH

It changes the specific heat

8. Choose the terms that best complete the statement: Identify an atom's major subatomic particle charges:

Protons (+) positive, Neutrons are neutral, electrons (-) negative

Protons are neutral, neutrons are the nucleus, electrons (-) negative

Protons (-) negative, neutrons (+) positive, electrons (-) negative

Protons (+) positive, neutrons (-) negative, electrons are neutral

9. Identify the property of water represented in this diagram:

Capillary Action

Polarity

Universal solvency

Surface tension

10. Identify: At the surface of a liquid, when water molecules absorb enough energy to change to a gas, the water molecules______________

Evaporate

Condense

Liquify

Solidify

11. A compound is different from an element because a compound is:

Made of two or more elements chemically combined.

The building block of all matter.

A mixture of elements.

A pure substance.

12. In testing, measurements are:

Controls

Observations

Variables

Data

13. Why do hydrogen atoms usually exist as molecules, H2?

Hydrogen has an atomic number of two and does not need to share

Hydrogen usually combines with other atoms to form covalent bonds

Hydrogen has one proton and is in search of one neutron

14. A summary of the relationship between the hypothesis and the test results.

Theory

Hypothesis

Conclusion

Data

15. Water is a universal solvent because:

Water is polar and can dissolve more substances than any other liquid

Solutes are not polar molecules

Water is made up hydrogen and oxygen atoms

Water has a neutral pH

16. What is a valence electron?

Ionically bonded electrons

Electrons in the outer most cloud of an atom

A negatively charge ion

A positively charge ion

17. This diagram represents H_2. What does the H₂symbol mean?

The H2 symbol represents two atoms of Hydrogen.

The H2 symbol represents a Hydrogen atom.

The H2 symbol represents a water molecule.

The H2 symbol represents an ionic bond.

18. Identify which property of water allows water to move against gravity.

Capillary Action allows water to move against gravity.

Surface tension allows water to move against gravity.

Cohesion allows water to move against gravity.

Universal solvency allows water to move against gravity.

19. In the pile or water lab: What is the key factor in determining what kind of container of water can hold the most pennies before spilling over?

The size of the container aperture (opening)

The mass of the container

The volume of water the container holds

The weight of the pennies

20. A suggested solution to a problem question.

Theory

Hypothesis

Conclusion

Data

21. How are covalent and ionic bonds different?

Covalent bonds have a neutral electronegativity. Ionic bonds create anions.

Covalent bonds make new elements. Ionic bonds create cations and anions.

22. What forms when one substance dissolves another?

Solution

Solvent

Dissolution

Solute

23. Why do hydrogen atoms usually exist as molecules, H2?

Hydrogen has an atomic number of two and does not need to share

Hydrogen usually combines with other atoms to form covalent bonds

Hydrogen has one proton and is in search of one neutron

24. What is an emulsion?

A mixture of liquids that do not dissolve in each other. One liquid is suspended within the other liquid.

When one liquid repels another and is neutral.

When a solute dissolves in a solvent.

When a liquid solidifies.

25. What property of water helps regulate the rate at which air changes temperature?

Specific heat

Evaporation

Condensation

Specific gravity

26.

Look over the Hydrologic Cycle diagram. Identify: the name of the discharge of water to the atmosphere by land and plants: ____________________

Evapotranspiration

Precipitation

Condensation

Evaporation

27. What is adhesion?

Waters ability to stick to other materials

Waters ability to stick to itself

Covalent bonds in water

Capillary Action

28. Identify: a substance that is being dissolved is a _________________

Solute

Solution

Solvent

Insoluble

29. Pepper and Soap Lab: Why did the pepper move to the sides of the Petri dish when the soap drop entered the water?

Where the soap enters the water the pepper scatters to avoid the soap micelles from surrounding it.

30. Which property is responsible for allowing water (and its dissolved substances) to move through the roots of plants and through the tiny blood vessels in our bodies?

Polarity

Surface tension

Universal solvency

Capillary Action

31. Ionic bonding allows atoms to have complete outer shells by:

Ionic bonding is a chemical compound formed by the joining of two or more atoms.

An ionic bond forms a stable compound through the sharing and transfer of valence electrons.

32. What is the difference between a compound and a mixture?

A compound is set of element that are blended but not chemically combined. A mixture is made up of emulsifiers.

33. The procedure to test an idea.

Theory

Process

Experiment

Control

34. The term ____________ is applied to any substance that cannot be made simpler without changing its chemical make-up.

Element

Atom

Molecule

Substance

35. A substance that dissolves another substance is called a ____________?

Solvent

Solution

Dissolution

Solute

36. You Can't Fix What Won't Mix:

What causes the food coloring to behave as it does when it is dropped into the graduated cylinder of oil and water?

The food coloring is oil based and floats through the water to reach the oil.

37. Identify the water property represented in this diagram: (Too zoom the image, either double tap or use 2 fingers spread to zoom)

Polarity

Specific heat

Universal solvency

Surface tension

38. What is an ion?

An negatively charged particle (atom or molecule).

The electrically charged particles of Ca2+, Mg2+ presence in water.

An electrically charged particle (atom or molecule) whose charge is determined by the loss or gain of electrons.

An electrically charged particle (atom or molecule) whose charge is determined by the sharing of electrons.

39. The atoms of each element have a unique number of protons in their nuclei.This unique number of protons is called the:

Atomic number

Atomic mass

Subatomic particles

Nucleus

40. What is matter?

Matter has mass, takes up space and can exist as a solid, liquid or gas.

Matter is made up of atoms and has weight.

Matter is made up of elements and has weight.

Matter has weight, takes up space and can exist as a solid and liquid only.

41. What is wicking?

A material that pulls moisture through by capillary action

Adhesion of water

Cohesion of water

Capillary Action of water

42. Which response best states why water is considered a polar molecule?

43. Identify the property of water that explains why water forms drops.

Cohesion causes surface tension

Polarity

Capillary action

Specific heat

44. What property of water makes it vulnerable to pollution?

Universal solvent

Polarity

Surface Tension

Capillary Action

45. What makes valence electrons different from other electrons?

Being in the outer shell, valance electrons can be shared or transferred (removed from or attached to) other atoms.

A valence electron is ionic and can be a cation or an anion.

A valence electron determines the electronegativity of an atom.

46. What is an amphiphilic molecule?

A molecule is amphiphilic when it has both a hydrophilic head and hydrophobic tail.

A molecule is amphiphilic when it has both a hydrophilic tail and hydrophobic head.

A molecule is amphiphilic when it is made up of covalent and ionically bonded compounds.

A molecule is amphiphilic when it is dispersed into a soap.

47. Identify the statement that is correct about the number of protons and electrons in an atom:

The number of protons and the number of electrons in an atom are always equal.

The number of protons is always greater than the number of electrons in an atom.

The number of protons is always less than the number of electrons in an atom.

The number of protons and electrons equals the mass of an atom.

48.

Identify the letter of the Hydrologic Cycle given in this question.Letter D is _________________

Streamflow

Groundwater discharge

Snowmelt runoff to streams

Water storage in oceans

Water storage in the atmosphere

Condensation

Evaporation

Sublimation

Evapotranspiration

Surface Runoff

Precipitation

Water storage in ice and snow

Infiltration

Groundwater storage

Spring

Freshwater storage

49. What is electronegativity?

How many electrons are in a valence.

The strength of an atoms' electrons.

The electrical charge of a polar molecule.

The exchange of electrons in ionic bonding.

50. Identify this chain:

This is a hydrocarbon chain of a soap molecule.

This is a food molecule chain.

This is an oxygen, hydrogen and carbon water molecule chain.

This is a soap molecule chain with sodium.

51. Waters high specific heat has a great deal to do with regulating extremes in the environment. How does water's specific heat capacity help the fish in the pond?

52.

Identify the letter of the Hydrologic Cycle given in this question.Letter H is _________________

Water storage in oceans

Water storage in the atmosphere

Condensation

Evaporation

Sublimation

Evapotranspiration

Surface Runoff

Precipitation

Water storage in ice and snow

Infiltration

Groundwater storage

Spring

Freshwater storage

Streamflow

Groundwater discharge

Snowmelt runoff to streams

53. Identify the statement that is correct about the number of protons and electrons in an atom:

The number of protons and the number of electrons in an atom are always equal.

The number of protons is always greater than the number of electrons in an atom.

The number of protons is always less than the number of electrons in an atom.

The number of protons and electrons equals the mass of an atom.

54. Oil and Water Paper Towel Climb Test:What caused the water to climb higher on the paper towel than the oil?

55. What characteristic of water explains why it has many unusual properties?

Water is a polar molecule.

Water is a nonpolar molecule.

Water molecules do not have electrically charges particles.

Water is a universal solvent.

56. Choose the correct term to fill in the blank. The Earth's __________ pulls on air, and this pull, or "pressure" of air, is called atmospheric pressure.

Gravity

Density

Volume

Air Pressure

57.

In the water pressure lab, of the two containers and three holes: Which container and which container hole had the least amount of water coming out when the hole was un-taped?

Capped, top hole

Uncapped, top hole

Uncapped, middle hole

Capped, middle hole

58. An explanation of how nature works.

Theory

Conclusion

Law

Hypothesis

59.

Identify the letter of the Hydrologic Cycle given in this question. Letter I is _________________

Streamflow

Groundwater discharge

Snowmelt runoff to streams

Water storage in oceans

Water storage in the atmosphere

Condensation

Evaporation

Sublimation

Evapotranspiration

Surface Runoff

Precipitation

Water storage in ice and snow

Infiltration

Groundwater storage

Spring

Freshwater storage

60. Identify the three parts of the micelle in this diagram in 1, 2, 3 order:

1. Water 2. polar Hydrophilic head 3. nonpolarHydrophobic tail

1. Air 2. polar Hydrophilic head 3. nonpolarHydrophobic tail

1. Water 2. nonpolar Hydrophobic tail 3. polar Hydrophilic head

1. Water 2. polar Hydrophilic tail 3. nonpolarHydrophobic head

61. Water Pressure Lab: Observe these containers:What is the greatest source of the pressure exerted on the water?

Air

Gravity

Water

Surface tension

62. A factor in an experiment that measures the effect in response to the test factor.

Variable

Independent variable

Dependent variable

Data

63. A statement that describes nature's behavior.

Law

Hypothesis

Theory

Conclusion

64. What is demonstrated about water in the 'Follow the String' activity?

Cohesion and adhesion.

Surface tension and adhesion.

Cohesion and capillary action.

Adhesion and capillary action.

65. This image shows two soda bottle streamsLook at this image to answer the question below. Soda bottle stream lab: The soda bottle has vertical cuts for the water to pour out. As the water exits the bottle it forms two individual streams. Identify the property of water that, with each pinch of your fingers, causes the water to combine and flow as one stream of water.

66. In the water pressure labs: What would you predict about the water coming out of the container if the container holes were made smaller?

67. In an experiment, the factor that is isolated to test the suggested problem solution.

Data

Independent variable

Variable

Dependent variable

68. In a bathroom shower: What property of water causes it to 'catch' and 'pull' together along the shower wall?

Surface tension of the water

Cohesion of the water

Polarity of the water

Specific heat of the water

69. What is an elements' relationship to an atom?

Elements are composed of identical atoms. Identical atoms make-up an element.

Elements are composed of different kinds of atoms.

Elements combine to make atoms.

Atoms are made up of subatomic particles.

70. Which force is capillary action related to?

Adhesion

Cohesion

Surface Tension

Polarity

71. Why are Hydrogen covalent bonds non-polar?

72.

In the water pressure lab: What do you predict would happen to the water coming out of the container if the container holes were larger?

If the holes were larger, the volume of water flowing is greater, but slower with less pressure.

If the holes were larger, the volume of water flowing is less, but faster with more pressure.

If the holes were larger, the volume of water flowing is greater, faster and with more pressure.

If the holes were larger, the volume of water flowing is greater, faster and with less pressure.

73. What is a chemical bond?

A chemical bond is the force that holds atoms together.

A chemical bond is the nucleus energy level that holds atoms together.

A chemical bond is the exchange of valence electrons.

A chemical bond is the pairing and sharing of electrons.

74. Consider the diagram and apply what you know to respond to this question: Why does water react differently to heat than most substances?

75. Which of these is a list of mixtures?

This is a list of mixtures: Air, soil, wood, gasoline, concrete and orange juice.

This is a list of mixtures: Air, soil, saltwater, wood, gasoline, concrete and orange juice.

This is a list of mixtures: Air, soil, water, wood, gasoline, concrete and orange juice.

This is a list of mixtures: Air, soil, wood, gasoline, H2, O2,

76. Refer to the diagram above and apply your knowledge. What changes as a water molecule cools?

77. The water and air pressure lab:If the lab were done while climbing Mt. Everest, as altitude increases what happens?

78. Water Pressure Lab: Observe these containers: Identify which bottle of water is under the greatest pressure?

Bottle with the cap off

Cap-on, bottle with the widest opening

Cap-on, bottle with the narrowest opening

None of these

79. A rainy day, think about a car windshield: What causes the raindrops to hold on to the windshield?

Surface tension of the water against the glass

Adhesion of the water to the glass

Polarity of the water

Specific heat of the water

80. What did Ben Franklin's experiment with nonpolar substances accurately measure?

Ben Franklin accurately measured the thickness of a single-molecule thick layer of olive oil on water.

Ben Franklin accurately measured the pollution in the pond water caused by the olive oil.

Ben Franklin accurately measured the change in surface tension when olive oil was added to the pond.

Ben Franklin accurately measured the area of underwater visibility created by altered surface tension when oil was added to water.

81. In this diagram, the e- represents:

The e- represents the covalent Hydrogen electron bond in this Hydrogen molecule.

The pair of e- represents the double covalent Hydrogen electrons in the Hydrogen molecule.

The pair of e- represents the ionic Hydrogen electrons in this Hydrogen molecule.

The e- represents a single shared Hydrogen electron in this Hydrogen molecule.

82. A Magic cup of water: What two forces act to keep the cardboard in place?

Surface tension and air pressure

Adhesion and cohesion

Surface Tension and adhesion

Adhesion and capillary action

83. How do soap micelles work?

Micelles cluster on the hydrophobic ends of water molecules so that their polar heads can trap oil and dirt.

Micelles cluster on the hydrophilic ends of water molecules so that their nonpolar tails can trap oil and dirt.

84. A meniscus formed in a graduated cylinder is caused by and an example of what?

Adhesion

Cohesion

Surface Tension

Capillary Action

85. The identity of an atom is determined by its number of ____________________.

Protons

Neutrons

Protons and neutrons

Electrons

8th Grade First Semester Mid-term Exam