Starr Science Review

Sulfur is a nonmetal. Of the following, the physical characteristic that is most likely to describe a sample of sulfur is —

• a shiny appearance

• brittleness

• malleability

• ductility

Potassium nitrate is a compound used in some fertilizers. Its chemical formula

is KNO3. How many TOTAL atoms are in each unit of potassium nitrate?

• 2

• 5

• 3

• 9

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Look at the pictures above. A shows the bag before the vinegar and baking soda are mixed together, and B shows it after they are mixed together. In which picture do the contents of the bag have the greater mass?

• The mass is greater in A—before they are mixed.

• The mass is greater in B—after they are mixed.

• The mass is the same in both.

• The mass depends on the temperature.

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A student uses a magnet to move a .04 kg ball bearing. The magnet exerts a force of 4N, which causes the ball bearing to begin moving. What is the acceleration of the ball bearing when it begins to move?

• .01 m/s2

• .16 m/s2

• 3.96 m/s2

• 100 m/s2

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NGSS.MS-PS2-2

While practicing in a simulator, an astronaut experienced an acceleration of 26 m/s2. The astronaut's mass was 63.0 kg. In Newtons, what force did the astronaut experience?

• 2.42 N

• 37 N

• 1638 N

• 42,588 N

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In this model, which particle determines the reactivity of this atom?

• Particle W

• Particle X

• Particle Y

• Particle Z

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A student is studying the ways different elements are similar to one another. Diagrams of atoms from four different elements are shown below.
Which two atoms are of elements in the same group in the periodic table?

• Atom 1 and Atom 2

• Atom 1 and Atom 4

• Atom 2 and Atom 3

• Atom 3 and Atom 4

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NGSS.MS-PS1-1

The scientist spilled a few drops of dilute hydrochloric acid (HCl) on a lab table. For safety purposes, the scientist sprinkled some baking soda (NaCO₃) onto the spill. Which observation would provide the best evidence that a chemical reaction occurred?

• The baking soda and hydrochloric acid combined, and bubbles formed.

• The baking soda absorbed the hydrochloric acid.

• Some of the baking soda dissolved in the hydrochloric acid.

• The hydrochloric acid evaporated, leaving only the baking soda.

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Many processes occur in the digestive system. Which process is best classified as a physical change?

• Saliva converting starch molecules in crackers to simple sugars

• Digestive enzymes breaking down proteins into smaller fragments

• Bacteria converting lactose into simple sugars in the intestines

• Teeth grinding an almond into smaller pieces in the mouth

Which of the following best describes an electron?

• It has no charge and about the same mass as a proton

• It has a negative charge and much less mass than a proton

• It has a positive charge and much more mass than a neutron

• It has a negative charge and about the same mass as a neutron

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