Calculating Molecular Mass and Formulas

The video tutorial explains the concept of relative molecular mass, starting with the basics of relative atomic mass using carbon-12 as a standard. It demonstrates how to calculate the relative molecular mass by summing the relative atomic masses of constituent atoms in a molecule. Examples include simple molecules like hydrogen and water, as well as more complex ones like methane and methanol. The video concludes with a summary of the key points and emphasizes the use of unified mass units.

What is the standard unit used for measuring relative atomic mass?

• Unified mass (U)

• Gram

• Mole

• Kilogram

How is the relative molecular mass of carbon dioxide determined?

• By multiplying the atomic masses of its atoms

• By dividing the atomic masses of its atoms

• By subtracting the atomic masses of its atoms

• By adding the relative atomic masses of its atoms

What is the relative molecular mass of a hydrogen molecule?

• 1 U

• 4 U

• 2 U

• 3 U

How do you calculate the relative molecular mass of a chlorine molecule?

• Add the atomic masses of two chlorine atoms

• Multiply the atomic masses of two chlorine atoms

• Subtract the atomic masses of two chlorine atoms

• Divide the atomic masses of two chlorine atoms

What is the relative molecular mass of a water molecule?

• 18 U

• 16 U

• 22 U

• 20 U

Which of the following is the relative molecular mass of methane?

• 12 U

• 16 U

• 18 U

• 14 U

What is the formula for ethane?

• C3H8

• C3H6

• C2H6

• C2H4

How is the relative molecular mass of ammonia calculated?

• By multiplying the atomic masses of one nitrogen and three hydrogen atoms

• By adding the atomic masses of one nitrogen and three hydrogen atoms

• By dividing the atomic masses of one nitrogen and three hydrogen atoms

• By subtracting the atomic masses of one nitrogen and three hydrogen atoms

What is the relative molecular mass of methanol?

• 34 U

• 30 U

• 32 U

• 36 U

What is the significance of the unit 'U' in measuring molecular mass?

• It represents a kilogram

• It is a measure of temperature

• It stands for unified mass

• It is a measure of volume