Calculating Molecular Mass and Atomic Mass

This video tutorial on the Fiven Chemistry channel teaches how to calculate the relative molecular mass (Mr) of compounds using atomic mass (Ar) values from the periodic table. It covers step-by-step calculations for various compounds, including NaOH, NaNO3, CH4, Ca3(PO4)2, MgSO4, Na2HPO4, and hydrated compounds like CuSO4·5H2O. The tutorial is aimed at 10th-grade chemistry students and provides detailed explanations to ensure understanding of the calculation process.

What is the primary tool used to find the relative atomic mass (Ar) for calculating molecular mass?

• Periodic Table

• Chemical Equation

• Molecular Formula

• Chemical Reaction

How do you calculate the molecular mass of NaOH?

• Add the Ar of Na, O, and H

• Divide the Ar of O by Na

• Multiply the Ar of Na by 2

• Subtract the Ar of H from Na

What is the molecular mass of NaNO3?

• 85

• 40

• 58

• 63

Which element's Ar is multiplied by 3 in the calculation of Ca3(PO4)2?

• Hydrogen (H)

• Oxygen (O)

• Phosphorus (P)

• Calcium (Ca)

What is the molecular mass of MgSO4?

• 120

• 400

• 142

• 310

How many water molecules are associated with CuSO4 in its hydrated form?

• 3

• 5

• 7

• 12

What is the molecular mass of CuSO4·5H2O?

• 249.5

• 159.5

• 90

• 400

In the calculation of MgSO4·7H2O, what is the total mass of the water molecules?

• 216

• 64

• 90

• 126

What is the molecular mass of KAl(SO4)2·12H2O?

• 310

• 120

• 258

• 474

What is the Ar of nitrogen (N) used in the calculation of Mg(NH4)PO4?

• 14

• 12

• 16

• 31