Term 1 Chemical Calculations

Question 1

Define mole

Answer 1

The mole is a unit of measurement used in chemistry to express amounts of a chemical substance. One mole of any substance contains approximately 6.022 x 10^23 elementary entities (atoms, molecules, ions, or other particles). This number is known as Avogadro’s number. The mole is often used to convert between the mass of a substance and the number of atoms or molecules it contains.

One mole of carbon atoms weighs approximately 12 grams, and it contains approximately 6.022 x 10^23 carbon atoms.

symbol: mol

Question 2

Define Molar mass

Answer 2

Molar mass is the mass of one mole of a substance. It is expressed in grams per mole (g/mol).

symbol: M

Question 3

How to convert moles to number of particles

Answer 3

Number of Particles (N) = Number of moles (n) x Avogadro’s number 6.022 x 10^23 particles/mol (NA)

Question 4

Convert particles to moles

Answer 4

number of moles (n) = number of particles (N) / Avogadro’s number 6.022 x 10^23 particles/mol (NA)

Question 5

How to calculate the molar mass of elements and compounds

Answer 5

Molar mass is calculated by summing the atomic masses of all atoms in a molecule using the atomic masses found on the periodic table.

The molar mass of water (H2O) is approximately 18.015 g/mol. This value is obtained by adding the atomic masses of two hydrogen atoms (1.008 g/mol each) and one oxygen atom (16.00 g/mol).

Question 6

Use molar mass to convert between mass (m) and moles (n = m / M)

Answer 6

Number of moles (n) = Mass of substance in grams (m) / Molar mass of the substance (in grams per mole) (M)

Question 7

convert moles (n) to mass (m)

Answer 7

Mass of substance in grams (m) = Number of moles (n) × Molar mass of the substance (in grams per mole)