Mole and mole calculations

Question 1

Moles of a substance

Answer 1

Mass (g) / Molar mass
mass = molar mass . moles
OR
moles of a substance- no. of particles / Avogadros no, (Na)

Avogadros no. - 6.022 x 10^23

Question 2

Concentration of a substance?

Answer 2

conc. - moles/volume
no. of moles = vol. x conc.