Unit 5: MOLECULE – ELEMENT – COMPOUND Lesson 3

A jar for oxygen gas contains

• O₂ molecules

• Individual oxygen atoms are not united with each other.

• A giant macromolecule contains many oxygen atoms. 

• An O₂ molecule

The copper electric wire core contains

• Cu₂ molecules

• Individual Cu atoms are not united with each other

• Lots of Cu atoms are united together

• a Cu molecule

Molecules of a single substance?

• Copper, Oxygen , Salt

•   Copper, Oxygen ,Helium

• Copper, Carbon dioxide , Salt

• Copper, Helium, Carbon dioxide

Molecules of a compound?

• Copper, Oxygen

•   Carbon dioxide, Helium

• Copper, Salt

• Carbon dioxide , Salt

In the following chemicals: Li, N₂, CO, Cl₂, S₈, NaCl. Which substances are single substances?

• Li, N₂, Cl₂, S₈.

• Li, N₂, CO, Cl₂.

• Li, N₂, CO, S₈, NaCl

• Li, N₂, CO, S₈, NaCl.

In the following chemicals: Li, N₂, CO, Cl₂, S₈, NaCl. Which substances are  compounds?

• CO, Cl₂

• CO, NaCl.

• Li, CO, Cl₂

• Cl₂, S₈, NaCl.

A water molecule contains two atoms of hydrogen and one of oxygen. Water is

•  compound

•  single substance

•  mixture

•  chemical element

Neon lamp contains

• Neon gas molecules ( Ne2).

• Individual neon ( Ne)  atoms are not united with each other

• giant macromolecule contains many neon atoms

• a neon atom

Image 5.4. Describes a molecule containing carbon, hydrogen, and oxygen.The number of atoms of each element of carbon, hydrogen, and oxygen present in a molecule of this substance is respectively

• 1, 6, 2.

• 2, 5, 1.

• 2, 6, 1.

• 6, 2, 1.

Use the atomic mass values ​​of some elements in the periodic table to calculate the molecular masses of the substances shown in the figure.

• Nitrogen  molecule:

   2.14 = 28 (amu).

  Methane molecule:

   12 + 4.1 = 16 (amu)

  Water molecule

   1.2 + 16 = 18 (amu)

   

• Nitrogen  molecule:

   2.16 = 32 (amu).

  Methane molecule:

   12 + 4.1 = 16 (amu)

  Water molecule

  1.2 + 16 = 18 (amu)

• Nitrogen  molecule:

   2.14 = 28 (amu).

  Methane molecule:

   12 + 1 = 13 (amu)

  Water molecule

  1.2 + 16 = 18 (amu)

   

• Nitrogen  molecule:

   2.12 = 24 (amu).

  Methane molecule:

   12 + 4.1 = 16 (amu)

  Water molecule

  1.2 + 16 = 18 (amu)