Organization of Matter Test Review

CO₂ represents carbon dioxide. What atoms make up one molecule of carbon dioxide?

• Two carbon atoms and one oxygen atom?

• One carbon atom and 2 oxygen atoms

• One carbon atom and one oxygen atom

• Two carbon atoms and two oxygen atoms

The chemical formula for sodium sulfate is Na₂SO₄. How many sulfur atoms are there in one molecule?

• 2

• 1

• 3

• 4

Carbonic acid has a chemical formula of CH₂O₃. How many oxygen atoms are in one molecule of carbonic acid?

• 1

• 6

• 2

• 3

Why do atoms form bonds?

• So they can gain more mass

• To become more energetic

• To change from a liquid to a solid

• To become more chemically stable

What type of bond is shown here?

• Ionic

• Covalent

• None of these

• Metallic

When an atom donates an electron and another atom takes an electron, what type of bond is being created?

• Covalent

• Ionic

• Magnetic

• Hydrogen

Which statement best describes the atoms of elements that form compounds by covalent bonds?

• They share electrons between them

• They have a large difference in atomic mass

• They are in the same period in the periodic table

• They have a large difference in valence electrons

Which choice best completes this sentence.

H₂O contains one____

• Element

• Oxygen atom

• Oxygen Molecule

• Hydrogen atom

According to the law of conservation of mass, which statement about chemical reactions is true?

• Every atom destroyed in a chemical reaction must be replaced

• Energy is created as atoms are destroyed in a chemical reaction

• Elements are created by some reactions and destroyed by others

• Atoms cannot be created or destroyed in a chemical reaction

In a closed system chemical reaction, the total mass of the reactants is 20 grams. After the reaction, what will the total mass be

• Exactly 10 grams

• Exactly 20 grams

• Less than 20 grams

• More than 20 grams