Compounds and Molecules Classification

Mr. Knight's lesson explores the differences between compounds and molecules. He begins with a pre-test, asking students to classify substances as compounds or molecules. Definitions are provided: compounds contain different elements chemically combined, while molecules can have the same or different elements. Examples like Na2CO3, O2, and CO2 are discussed to illustrate these concepts. A chart is analyzed to further classify substances. The lesson concludes with the key point that all compounds are molecules, but not all molecules are compounds.

What is the main focus of the pre-test given by Mr. Knight?

• To calculate the mass of molecules

• To understand chemical reactions

• To distinguish between compounds and molecules

• To identify elements in a compound

Which of the following best describes a compound?

• Atoms of the same element combined

• Atoms of two or more different elements chemically combined

• Atoms of two or more elements, same or different, chemically combined

• Atoms of a single element

How does a molecule differ from a compound?

• Molecules contain only different elements

• Molecules can contain the same or different elements

• Molecules are not chemically combined

• Molecules are always larger than compounds

Why is Na2CO3 considered both a compound and a molecule?

• It contains only one type of atom

• It is not chemically combined

• It contains different elements chemically combined

• It contains atoms of the same element

Which of the following is only a molecule and not a compound?

• H2O

• CO2

• O2

• NaCl

What is the classification of N2?

• Element

• Compound

• Mixture

• Molecule

Why can't Cl be classified as a molecule?

• It is a compound

• It contains different elements

• It contains only one atom

• It is not chemically combined

What is the classification of Cl2?

• Mixture

• Element

• Molecule

• Compound

What is the key takeaway about compounds and molecules?

• Compounds are not chemically combined

• Compounds and molecules are the same

• All compounds are molecules

• All molecules are compounds

What is Cl classified as?

• Molecule

• Mixture

• Compound

• Element