Question 1

Nanoscience has shown that ________.

Accepted Answer

A)   a chemical occurs with the use of a scanning probe microscope
B)   the properties of a material can be different on the level of atoms then its properties when the material is analyzed in bulk
C)   a physical change can occur when using a scanning probe microscope
D)   DNA is the smallest molecule B

Question 2

If you eat metallic sodium or inhale chlorine gas, you stand a strong chance of dying. Let these two elements react with each other, however, and you can safely sprinkle the compound on your popcorn for better taste. What is going on?

Accepted Answer

A)   After these two elements react they lose the potential energy to cause harm.
B)   All elements are inherently dangerous
C)   Sodium and chlorine from the elemental form is more concentrated than the sodium and chlorine we get from sodium chloride.
D)   Sodium chloride has nothing in common with the properties of the elements sodium and chlorine. D

Question 3

The following image represents which kind of matter?

Accepted Answer

A)   a mixture
B)   a compound
C)   an element
D)   none of the above
E)   all of the above A

Question 4

Germanium, Ge (number 32), computer chips operate faster than silicon, Si (number 14), computer chips. So how might a gallium, Ga (number 31), chip compare with a germanium chip?

Accepted Answer

A)   A gallium chip would be even faster because the gallium is more metallic.
B)   A gallium chip would be slower because its electrons are more loosely held.
C)   Gallium is located just below aluminum, which is widely known to be an electrical insulator.
D)   Gallium is more nonmetallic and so it does not conduct electrons very well.

Question 5

Which of the following is a pure substance?

Accepted Answer

A)   baking soda
B)   salt water
C)   cooking oil
D)   duct tape
E)   orange juice

Question 6

Based on the information given in the following diagrams, which substance has the lower boiling point: one made from molecule A or one made from molecule B?

Accepted Answer

A)   molecule A because it is the first to transform into a liquid
B)   molecule B because it is first to transform into a liquid
C)   molecule A because it remains in the gaseous phase
D)   molecule B because it remains in the gaseous phase

Question 7

Water and ethanol can be separated by heating the ethanol until it boils away from the water. What type of change is this?

Accepted Answer

A)   a physical change
B)   a chemical change
C)   a molecular change
D)   a decomposition
E)   none of the above

Question 8

Classify the following changes as physical or chemical. Wood burns to ashes; water begins to boil; grass grows; a rock is crushed to powder.

Accepted Answer

A)   chemical; physical; chemical; chemical
B)   chemical; physical; physical; physical
C)   physical; physical; chemical; physical
D)   chemical; physical; chemical; physical

Question 9

A skillet is lined with a thin layer of cooking oil followed by a layer of unpopped popcorn kernels. Upon heating the kernels all pop thereby escaping the skillet. Which of the following physical and/or chemical changes occurred?

Accepted Answer

A)   The water within each kernel is heated to the point that it would turn into water vapor as the kernels popped (physical change) .
B)   The starches within the kernels are cooked by the high temperatures (chemical change) .
C)   Both A and B occur.
D)   Physical and chemical changes cannot occur without a real chemical reaction taking place.

Question 10

The scanning probe microscope ________.

Accepted Answer

A)   uses very large mirrors and lenses to enhance an image
B)   can scan small things from a large distance away, such as the surface of the Moon
C)   characterizes the surface atoms of a material
D)   vaporizes a substance, then analyzes and manipulates the components

Question 11

Which of the following elements will most likely be shiny and flexible?

Accepted Answer

A)   rhodium (Rh) 
B)   hydrogen (H) 
C)   selenium (Se) 
D)   iodine (I) 
E)   silicon (Si)

Question 12

Which chemical family is composed almost entirely of synthetic elements?

Accepted Answer

A)   the actinides
B)   the lanthanides
C)   the halogens
D)   all of the above
E)   none of the above

Question 13

A chemical change involves a change in ________.

Accepted Answer

A)   how atoms are bonded
B)   the elements of a molecule
C)   phase
D)   all of the above

Question 14

Why isn't dirt listed in the periodic table?

Accepted Answer

A)   The periodic table lists only elements made of one kind of material. Dirt is a mixture of elements and compounds.
B)   Elements like dirt and air are so common that there is no need to list them in the periodic table.
C)   Dirt IS listed in the periodic table but is not easily recognized because it is listed as one of the rare earths with its old scientific name, dysprosium, symbol Dy.
D)   None of the above is true.

Question 15

The following image represents which kind of matter?

Accepted Answer

A)   a compound
B)   a mixture
C)   an element
D)   none of the above
E)   all of the above

Question 16

What are metalloids?

Accepted Answer

A)   elements that have some properties like metals and some like nonmetals
B)   elements that are smaller than metals
C)   elements found in asteroids
D)   elements that are larger than nonmetals
E)   elements that have properties different than either the metals or the nonmetals

Question 17

What is the name of the following compound? SF3

Accepted Answer

A)   sulfur trifluoride
B)   sulfur fluoride
C)   trifluorosulphide
D)   fluorine sulphide
E)   none of the above

Question 18

Which of these properties describes a metal?

Accepted Answer

A)   conducts heat very well
B)   brittle
C)   fragile
D)   transparent
E)   doesn't conduct electricity very well

Question 19

Which of the following is a mixture?

Accepted Answer

A)   air
B)   gold
C)   salt
D)   iron
E)   helium

Question 20

How would you classify the following material? swimming pool water

Accepted Answer

A)   homogeneous mixture
B)   heterogeneous mixture
C)   a pure element
D)   a pure compound
E)   depends on how many children have been in it

Exam 3: Elements of Chemistry

Nanoscience has shown that ________.

If you eat metallic sodium or inhale chlorine gas, you stand a strong chance of dying. Let these two elements react with each other, however, and you can safely sprinkle the compound on your popcorn for better taste. What is going on?

The following image represents which kind of matter?

Germanium, Ge (number 32) , computer chips operate faster than silicon, Si (number 14) , computer chips. So how might a gallium, Ga (number 31) , chip compare with a germanium chip?

Which of the following is a pure substance?

Based on the information given in the following diagrams, which substance has the lower boiling point: one made from molecule A or one made from molecule B?

Water and ethanol can be separated by heating the ethanol until it boils away from the water. What type of change is this?

Classify the following changes as physical or chemical. Wood burns to ashes; water begins to boil; grass grows; a rock is crushed to powder.

A skillet is lined with a thin layer of cooking oil followed by a layer of unpopped popcorn kernels. Upon heating the kernels all pop thereby escaping the skillet. Which of the following physical and/or chemical changes occurred?

The scanning probe microscope ________.

Which of the following elements will most likely be shiny and flexible?

Which chemical family is composed almost entirely of synthetic elements?

A chemical change involves a change in ________.

Why isn't dirt listed in the periodic table?

The following image represents which kind of matter?

What are metalloids?

What is the name of the following compound? SF₃

Which of these properties describes a metal?

Which of the following is a mixture?

How would you classify the following material? swimming pool water