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1

Use the periodic table to identify the elements and numbers of atoms in the compound CO2.

One cobalt atom and one asmium atom

Two carbon atoms and one oxygen atom

One carbon atom and two oxygen atoms

Two cobalt atoms and two osmium atoms

7.6.B

1

Which statement correctly compares elements and compounds in terms of their atoms?

Elements and compounds are both made up of different kinds of atoms.

Elements are made up of one kind of atom, while compounds are made up of two or more kinds of atoms.

Compounds are made up of one kind of atom, while elements are made up of two or more kinds of atoms.

Both elements and compounds are made up of molecules only.

7.6.A

1

A student combines baking soda and vinegar and notices that the new substance has a lot of bubbles and is a different color.

Based on evidence from the student’s observation, what type of change is occurring?

A physical change, because a gas is formed

A physical change, because the color changes

A chemical change, because a gas is formed

A chemical change, because two substances are mixed

7.6.C

1

A student has 100 ml of hot water in a beaker and 100 ml of cold water in another beaker. They put 20 g of salt in each beaker and wait for one minute.

The salt will dissolve completely in both hot and cold water.

The salt will dissolve faster in the hot water than in the cold water

The salt will dissolve faster in the cold water than in the hot water.

The salt will not dissolve in either hot or cold water within one minute.

7.6.E

1

An element and a compound are shown below.
Helium (He)
Water (H₂O)
How do these examples show the difference between elements and compounds?

He is a compound because its chemical symbol consists of only one type of atom; H₂O is an element because its chemical formula shows it is made up of two different elements.

He is an element because it is made of only one type of atom; H₂O is a compound because it is made up of two hydrogen atoms and one oxygen atom.

He is a compound because it is made of two atoms of helium; H₂O is an element because it is made up of one hydrogen atom and one oxygen atom.

He is an element because it is made of only one type of atom; H₂O is a compound because it has hydrogen in it.

7.6.A

1

A student makes two changes to matter in the classroom. The student observes what happens to the matter and records the data in the table.
Are the experiments examples of physical changes, chemical changes, or both?

Melting an ice cube is a physical change because the ice cube only changed form. Mixing baking soda and vinegar is a chemical change because a new substance (a gas) was formed.

Melting an ice cube and mixing baking soda and vinegar are both physical changes because the ice, baking soda, and vinegar all change phase during the reaction.

Melting an ice cube and mixing baking soda and vinegar are both chemical changes because heat is created during both reactions.

Melting an ice cube is a chemical change because the ice cube changed form. Mixing baking soda and vinegar is a physical change because a new substance (a gas) was formed.

7.6.C

1

Saltwater is an aqueous solution because it is composed of salt and water. How would increasing the solute affect the solution?

It would increase the concentration of salt.

It would decrease the concentration of salt.

It would increase the concentration of water.

It has no effect on the concentration of salt.

7.6.D

1

How does the chemical formula CO₂ compare to the chemical formula H₂O in terms of composition?

CO₂ has two carbon atoms and two oxygen atoms; H₂O has two hydrogen atoms and two oxygen atom.

CO₂ has one carbon atom and two oxygen atoms; H₂O has two hydrogen atoms and one oxygen atom.

CO₂ has two carbon atoms and one oxygen atom; H₂O has 2 oxygen atoms and one hydrogen atom.

CO₂ has one carbon atom and one oxygen atom; H₂O has one hydrogen atom and one oxygen atom.

7.6.B

Unit 1 Pre Assessment

Unit 1 Pre Assessment

Use the periodic table to identify the elements and numbers of atoms in the compound CO2.

Which statement correctly compares elements and compounds in terms of their atoms?

A student combines baking soda and vinegar and notices that the new substance has a lot of bubbles and is a different color.

Based on evidence from the student’s observation, what type of change is occurring?

A student has 100 ml of hot water in a beaker and 100 ml of cold water in another beaker. They put 20 g of salt in each beaker and wait for one minute.

An element and a compound are shown below.
Helium (He)
Water (H₂O)
How do these examples show the difference between elements and compounds?

A student makes two changes to matter in the classroom. The student observes what happens to the matter and records the data in the table.
Are the experiments examples of physical changes, chemical changes, or both?

Saltwater is an aqueous solution because it is composed of salt and water. How would increasing the solute affect the solution?

How does the chemical formula CO₂ compare to the chemical formula H₂O in terms of composition?

Use the periodic table to identify the elements and numbers of atoms in the compound CO2.

Which statement correctly compares elements and compounds in terms of their atoms?

A student combines baking soda and vinegar and notices that the new substance has a lot of bubbles and is a different color.

Based on evidence from the student’s observation, what type of change is occurring?

A student has 100 ml of hot water in a beaker and 100 ml of cold water in another beaker. They put 20 g of salt in each beaker and wait for one minute.

An element and a compound are shown below.
Helium (He)
Water (H₂O)
How do these examples show the difference between elements and compounds?

A student makes two changes to matter in the classroom. The student observes what happens to the matter and records the data in the table.
Are the experiments examples of physical changes, chemical changes, or both?

Saltwater is an aqueous solution because it is composed of salt and water. How would increasing the solute affect the solution?

How does the chemical formula CO₂ compare to the chemical formula H₂O in terms of composition?

Unit 1 Pre Assessment

Unit 1 Pre Assessment

Use the periodic table to identify the elements and numbers of atoms in the compound CO2.

Which statement correctly compares elements and compounds in terms of their atoms?

A student combines baking soda and vinegar and notices that the new substance has a lot of bubbles and is a different color. Based on evidence from the student’s observation, what type of change is occurring?

A student has 100 ml of hot water in a beaker and 100 ml of cold water in another beaker. They put 20 g of salt in each beaker and wait for one minute.

An element and a compound are shown below.Helium (He)Water (H2O)How do these examples show the difference between elements and compounds?

A student makes two changes to matter in the classroom. The student observes what happens to the matter and records the data in the table.Are the experiments examples of physical changes, chemical changes, or both?

Saltwater is an aqueous solution because it is composed of salt and water. How would increasing the solute affect the solution?

How does the chemical formula CO2 compare to the chemical formula H2O in terms of composition?

Use the periodic table to identify the elements and numbers of atoms in the compound CO2.

Which statement correctly compares elements and compounds in terms of their atoms?

A student combines baking soda and vinegar and notices that the new substance has a lot of bubbles and is a different color. Based on evidence from the student’s observation, what type of change is occurring?

A student has 100 ml of hot water in a beaker and 100 ml of cold water in another beaker. They put 20 g of salt in each beaker and wait for one minute.

An element and a compound are shown below.Helium (He)Water (H2O)How do these examples show the difference between elements and compounds?

A student makes two changes to matter in the classroom. The student observes what happens to the matter and records the data in the table.Are the experiments examples of physical changes, chemical changes, or both?

Saltwater is an aqueous solution because it is composed of salt and water. How would increasing the solute affect the solution?

How does the chemical formula CO2 compare to the chemical formula H2O in terms of composition?

A student combines baking soda and vinegar and notices that the new substance has a lot of bubbles and is a different color.

Based on evidence from the student’s observation, what type of change is occurring?

An element and a compound are shown below.
Helium (He)
Water (H₂O)
How do these examples show the difference between elements and compounds?

A student makes two changes to matter in the classroom. The student observes what happens to the matter and records the data in the table.
Are the experiments examples of physical changes, chemical changes, or both?

How does the chemical formula CO₂ compare to the chemical formula H₂O in terms of composition?

A student combines baking soda and vinegar and notices that the new substance has a lot of bubbles and is a different color.

Based on evidence from the student’s observation, what type of change is occurring?

An element and a compound are shown below.
Helium (He)
Water (H₂O)
How do these examples show the difference between elements and compounds?

A student makes two changes to matter in the classroom. The student observes what happens to the matter and records the data in the table.
Are the experiments examples of physical changes, chemical changes, or both?

How does the chemical formula CO₂ compare to the chemical formula H₂O in terms of composition?