Molar Mass and Chemical Formulas

This video tutorial explains how to calculate the molar mass of copper(II) nitrate hexahydrate (Cu(NO3)2·6H2O). The process involves determining the molar mass of copper(II) nitrate and then adding the mass of six water molecules. The video provides step-by-step instructions, including the use of atomic masses from the periodic table. The final calculated molar mass is 295.69 grams per mole. The tutorial also notes that variations in periodic table values may lead to slight differences in the final result.

What is the chemical formula for copper(II) nitrate hexahydrate?

• CuCl2·2H2O

• CuSO4·5H2O

• Cu(NO3)2

• Cu(NO3)2·6H2O

What is the molar mass of copper as found on the periodic table?

• 60.08 g/mol

• 65.38 g/mol

• 58.44 g/mol

• 63.55 g/mol

How many oxygen atoms are present in one nitrate ion?

• Three

• Two

• Four

• One

What is the molar mass of a single nitrate ion?

• 14.00 g/mol

• 16.00 g/mol

• 62.00 g/mol

• 48.00 g/mol

What is the molar mass of water used in the calculation?

• 18.02 g/mol

• 15.99 g/mol

• 16.00 g/mol

• 20.00 g/mol

How many water molecules are added to the copper(II) nitrate in this compound?

• Six

• Five

• Four

• Seven

What is the final calculated molar mass of copper(II) nitrate hexahydrate?

• 280.00 g/mol

• 300.00 g/mol

• 250.00 g/mol

• 295.69 g/mol

Why might the calculated molar mass differ slightly when using different periodic tables?

• Different tables use different units.

• Tables are updated annually with new data.

• Periodic tables may round atomic masses differently.

• Some tables exclude certain elements.