7th Grade Final Review

What are the basic building blocks of all matter?

• Molecules

• Elements

• Atoms

• Compounds

What is an element?

• A mixture of two or more substances

• A chemical substance formed by different elements

• A substance consisting of one or more atoms of the same type

• A substance that cannot be broken down into simpler substances

What defines a molecule?

• A substance that cannot be chemically broken down

• A chemical substance formed by two or more elements in a specific proportion

• Atoms of the same type bonded together

• Two or more atoms bonded together, which can be the same or different

What is a compound?

• A mixture of two or more substances not chemically bonded

• A chemical substance formed when two or more different elements bond in a specific proportion

• A single type of atom

• A substance that changes its properties when mixed with another

Which of the following is a molecule but not a compound?

• KMnO4

• HCl

• Cl2

• Fe

What does the subscript in a chemical formula indicate?

• The number of molecules participating in the reaction

• The number of atoms of each element in the compound

• The total number of elements in the compound

• The physical state of the compound

How are chemical compounds different from mixtures?

• Compounds can be separated by physical means

• Compounds are always liquids

• Compounds consist of multiple elements chemically combined. (A pure substance)

• Mixtures are pure substances

Bonds between atoms in a molecule form as a result of

• valence electrons

• protons

• neutrons

What is the chemical formula for water as shown in the diagram?

• H20

• O2H

• HO2

• CH4

According to the diagram, what is the chemical formula for ammonia?

• N3H

• H3N

• 3HN

• 3NH