Chemistry Moles and Molar Mass: Key Concepts and Calculations

What is the SI unit of amount of substance?

The mole, symbol mol.

How many particles are in one mole of a substance?

6.02 x 10^23 particles, known as the Avogadro Constant.

What does one mole of sodium (Na) contain?

6.02 x 10^23 atoms of sodium.

What does one mole of hydrogen (H2) contain?

6.02 x 10^23 molecules of hydrogen.

What does one mole of sodium chloride (NaCl) contain?

6.02 x 10^23 formula units of sodium chloride.

What is the mass of one mole of an element?

It is the same as the relative atomic mass written in grams.

What is the molar mass of a compound?

It is the same as the relative molecular or formula mass in grams.

How many formula units are in 1 mole of magnesium chloride (MgCl2)?

6.02 x 10^23 formula units.

How many atoms are in 1 mole of magnesium chloride (MgCl2)?

18.06 x 10^23 atoms.

How many chloride ions are in 1 mole of magnesium chloride (MgCl2)?

12.04 x 10^23 chloride ions.

How many magnesium ions are in 2 moles of magnesium chloride (MgCl2)?

12.04 x 10^23 magnesium ions.

What is the relationship between moles and atomic mass?

One mole of any element is equal to the relative atomic mass of that element in grams.

What is the mass of 1 mole of carbon (C)?

12 grams.

What is the molar mass of water (H2O)?

18 grams (2 x 1 + 16).

How do you calculate the mass of a substance in grams from moles?

Mass = moles x molar mass.

What is the molar mass of zinc (Zn)?

65 g/mol.

What is the mass of 0.250 moles of zinc?

16.25 grams.

How do you find the number of moles from mass?

Number of moles = mass ÷ molar mass.

How many moles are in 2.64 g of sucrose (C12H22O11)?

7.72 x 10^-3 moles.

What is the molar mass of sucrose (C12H22O11)?

342 g/mol.