Calculating Molar Mass of Compounds

The video tutorial explains how to calculate the molar mass of sodium sulfide (Na2S). It begins by identifying the atomic masses of sodium and sulfur from the periodic table. The tutorial then demonstrates how to multiply the atomic mass of sodium by two, as there are two sodium atoms in Na2S, and adds the atomic mass of sulfur. The final molar mass of Na2S is calculated to be 78.05 grams per mole.

What is the first step in finding the molar mass of a compound like Na2S?

• Divide the atomic mass of sodium by the number of atoms.

• Look up the atomic masses of all elements in the compound.

• Directly add the atomic masses of the elements.

• Multiply the atomic mass of sulfur by two.

How do you calculate the total mass of sodium in Na2S?

• Divide the atomic mass of sodium by the number of sulfur atoms.

• Add the atomic mass of sodium to the atomic mass of sulfur.

• Subtract the atomic mass of sulfur from sodium.

• Multiply the atomic mass of sodium by the number of sodium atoms.

What is the atomic mass of sulfur used in the calculation of Na2S's molar mass?

• 44.01 grams per mole

• 78.05 grams per mole

• 22.99 grams per mole

• 32.07 grams per mole

What is the final molar mass of Na2S after adding the masses of sodium and sulfur?

• 55.99 grams per mole

• 64.06 grams per mole

• 78.05 grams per mole

• 90.07 grams per mole

Which element's mass is added last in the calculation of Na2S's molar mass?

• Sodium

• Sulfur

• Oxygen

• Hydrogen