7th Grade Unit Two Lesson Four Quiz

Which of these substances is a compound?

• carbon (C)

• chlorine gas (Cl₂)

• uranium (U)

• ammonia (NH₄)

If you were to look at grains of table salt (sodium chloride, NaCl) with a magnifying glass, you would see that each grain is a little cube. Why are salt grains cubical?

• All extended structure compounds form cubes.

• Sodium and chlorine atoms both have cubical shapes.

• In the extended structure of NaCl, atoms are arranged in a cubical pattern.

• A molecule of NaCl contains eight atoms, each at one of the corners of a cube

Sucrose is composed of carbon, oxygen, and hydrogen. Which statement best describes the properties of sucrose?

• They are exactly like the properties of carbon (C)

• They are exactly like the properties of oxygen (O)

• They are exactly like the properties of hydrogen (H)

• They are different from the properties of carbon, oxygen, and hydrogen

A molecule of methanol is composed of carbon atoms connected to 3 hydrogen atoms and a hydroxide group. A hydroxide group is made up of an oxygen atom bonded to a hydrogen atom. How many different types of atoms make up one molecule of methanol?

• 3

• 4

• 5

• 6

These models show the arrangement of particles in two solid materials.

Which statement describes a basic difference between these materials?

• X is a metal, and Y is a salt

• X is an element, and Y is a compound

• X is a crystal, and Y is amorphous

• X is made of single atoms, and Y is made of molecules

The diagram represents a chemical reaction.

Reactant A and reactant B react to form product C. What type of substance is product C?

• an atom

• a mixture

• an element

• a compound

Polyvinyl chloride (PVC) is a polymer used to make water pipes and other products. Polymer molecules are made of groups of atoms that repeat many times in long chains as shown in the formula.

Which circle, left to right, shows the repeating group of atoms that forms PVC?

• first circle

• second circle

• third circle

• fourth circle