which statement about pure substance and molecules is correct?

Question

a. pure substances cannot be molecules
b. all pure substance are molecules
c. all molecules are pure substance
d. molecules cannot be pure substances

Answer 1

The correct statement is:

c. all molecules are pure substances.

Explanation: A pure substance is defined as a material that has a consistent composition and specific properties, which can include elements and compounds (which are made of molecules). All molecules, which are made of two or more atoms bonded together, are considered pure substances if they have a uniform composition. However, not all pure substances are necessarily molecules, as some pure substances can be elemental forms (like gold or oxygen gas, which may exist as individual atoms or as diatomic molecules).