CBA 1 REVIEW 22

Gold is represented by the symbol Au on the Periodic Table of the Elements. This allows us to infer that gold is:

• a compound

• a pure substance

• made of synthetic atoms

• made of elements found on the Periodic Table

Rebekah is asked to create a bar graph containing the most common elements in Earth's atmosphere. Which of the following should not be included?

• O

• H

• N

• HF

Which of the following best describes a change in iron caused by a chemical reaction?

• An iron nail looks shiny and silvery

• An iron nail rubbed with a magnet attracts iron powder

• An iron wire left outside turns a rusty orange color

• An iron wire attached to a battery becomes hot.

Students mixed two liquids in a beaker and listed their observations.

Based on these observations, which statement contains the best evidence that a chemical reaction occurred?

• There is a change in shape.

• There is a change in volume.

• The two liquids mix into a solution.

• The two liquids form a new substance.

Which statement best describes evidence that a chemical reaction occurs as a cake bakes?

• The water in the cake batter evaporates.

• The cake rises as gas bubbles form in the baking cake.

• The cake takes the shape of the container in which it is baked.

• The water in the cake batter is used to keep the cake moist as it bakes

How many neutrons are in the nucleus of a potassium atom with a mass number of 39? Enter your answer in the space.

• 39

• 19

• 20

• 22

Which statement correctly describes the location and charge of the electrons in an atom?

• The electrons are inside the nucleus and have no charge.

• The electrons are outside the nucleus and have no charge.

• The electrons are inside the nucleus and have a negative charge.

• The electrons are outside the nucleus and have a negative charge.

The names and chemical formulas of four substances are shown in the chart.

Which substance listed in the chart is made up of the most atoms?

• Carbonic acid

• Nitric acid

• Phosphoric acid

• Sulfuric acid

Which statement correctly describes the location and charge of the electrons in an atom?

• The electrons are inside the nucleus and have no charge.

• The electrons are outside the nucleus and have no charge.

• The electrons are inside the nucleus and have a negative charge.

• The electrons are outside the nucleus and have a negative charge.