The Mole

Front

What is the definition of a mole in chemistry?

Back

A mole is a unit of measurement used to express the amount of a substance, defined as exactly 6.022 x 10^23 particles (atoms, molecules, ions, etc.).

Front

How do you calculate the molar mass of a compound?

Back

To calculate the molar mass of a compound, sum the atomic masses of all the atoms in its chemical formula, using the periodic table.

Front

What is the formula to convert grams to moles?

Back

Moles = Mass (grams) / Molar Mass (g/mol).

Front

How do you determine the percentage composition of an element in a compound?

Back

Percentage composition = (mass of the element in 1 mole of the compound / molar mass of the compound) x 100%.

Front

What is the molar mass of calcium nitrate (Ca(NO3)2)?

Back

The molar mass of calcium nitrate is approximately 164.1 g/mol.

Front

How many moles are in 98.9 grams of CaCl2?

Back

Moles = 98.9 g / 110.98 g/mol (molar mass of CaCl2) = 0.89 moles.

Front

What is Avogadro's number and its significance?

Back

Avogadro's number (6.022 x 10^23) is the number of particles in one mole of a substance, allowing for the conversion between moles and number of particles.

Front

How do you calculate the number of molecules in a given number of moles?

Back

Number of molecules = moles x Avogadro's number.

Front

What is the molar mass of water (H2O)?

Back

The molar mass of water is approximately 18.02 g/mol.

Front

How do you find the number of moles in a given mass of an element?

Back

Number of moles = mass of the element (grams) / atomic mass of the element (g/mol).