6 WEEKS TEST

A researcher wants to experiment with an element that reacts like phosphorus (P) but has a greater atomic mass. Which element should the researcher select for the experiment?

• Nitrogen (N)

• Sulfur (S)

• Arsenic (As)

• Silicon (Si)

A scientist spilled a few drops of dilute hydrochloric acid (HCl) on a lab table. For safety purposes, the scientist sprinkled some baking soda (NaHCO3) 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

Hay is made up of organic compounds. What are the main elements in many organic compounds?

• Helium, carbon, sodium

• Sodium, hydrogen, nitrogen

• Carbon, hydrogen, oxygen

• Radon, oxygen, helium

The model of the periodic table below shows the locations of four elements.

• 1

• 2

• 3

• 4

During an investigation, a student combined the two clear, colorless solutions.

The student observed that the temperature changed from 25°C to 23°C when the solutions were combined and that a white substance rapidly formed and settled to the bottom of the container. What most likely happened to produce these results?

• One of the original compounds came out of solution.

• The solutions reacted chemically.

• Some of the water froze into ice crystals.

• Rapid evaporation of water occurred, leaving a solid.

A scientist performed four investigations using eight different liquids. In each investigation, the scientist combined two of the liquids under a fume hood and recorded observations in the table below.

• 1

• 2

• 3

• 4

Some students conducted a laboratory investigation to learn more about the physical properties of different elements. They observed four samples and recorded their observations in the table below.

• Sample 1

• Sample 2

• Sample 3

• Sample 4

Aluminum, sulfur, and chlorine are elements found on the periodic table. Tests involving these three elements would show that at normal room temperature —

• sulfur is malleable and aluminum conducts electricity

• chlorine is malleable and conducts electricity

• aluminum is malleable and conducts electricity

• all three elements are malleable and conduct electricity

For an investigation a student poured a blue solution of CuSO into a beaker. The student 4 placed a shiny, silver-colored strip of zinc metal in the solution and observed the changes.

The student inferred that a chemical reaction occurred. What evidence supports this inference?

• A dark solid formed on the zinc metal.

• The zinc metal remained silver-colored and shiny

• The CuSO solution turned blue when the zinc metal was added

• None of these

Which of the following is a chemical change?

• water freezes to form ice
• sugar dissolves in water
• gasoline burns in a car engine
• a piece of metal expands when it is heated