Differences Between Compounds, Molecules & Mixtures

What is a molecule?

• A single atom

• A substance that contains two or more different elements

• A large structure containing millions of atoms

• A group of two or more atoms held together by chemical bonds

Which of the following is an example of a molecule?

• Oxygen (O2)

• Sodium Chloride (NaCl)

• Helium

• A mixture of gases

What defines a compound?

• A substance that contains only one element

• A substance that contains two or more different elements in a fixed ratio

• A large structure formed by ionic bonds

• A group of atoms bonded together that can be easily separated

Which of the following is NOT a compound?

• Sulfuric Acid (H2SO4)

• Water (H2O)

• Oxygen (O2)

• Carbon Dioxide (CO2)

What is the chemical formula for water?

• NaCl

• O2

• H2O

• CO2

What does the subscript in a chemical formula indicate?

• The atomic number of the element

• The number of molecules

• The charge of the atom

• The number of atoms of that element in the molecule

Which of the following is a characteristic of compounds?

• They only exist as small, simple molecules

• They are formed by physical mixing

• They can contain any number of elements in any proportion

• The elements in them are always found in the same proportions

What is a mixture?

• A substance with chemical bonds between different elements

• A group of molecules forming a large structure

• Two or more substances not chemically combined together

• A compound with a fixed ratio of elements

Which method is NOT used to separate mixtures?

• Distillation

• Chemical bonding

• Crystallization

• Filtration

What type of bond is found in sodium chloride (NaCl) that leads to the formation of large structures?

• Ionic bond

• Metallic bond

• Covalent bond

• Hydrogen bond