Chapter 9: The mole

Question 1

Equations for all substances to find number of mol

Answer 1

No. of mol = mass/molar mass

No. of mol = Number of particles/avogadro’s constant (6.02x10^23)

Question 2

What is the value for stp.?

Answer 2

22.7dm3/mol

Question 3

Equation for gases to find number of mol.

Answer 3

No. of mol = Volume/Molar volume (22.7dm3/mol)

Question 4

Name the units for concentration

Answer 4

Concentration (mol/dm3) = No. of mol of solute/volume

Concentration (g/dm3) = Mass of solute/volume

Concentration (g/dm3) = Concentration (mol/dm3) x molar mass (g/mol)
and vice versa

Question 5

How to find empirical formula

Answer 5

1) Find % of substances in a compound
2) Find Ar
3) Find no. of mol by dividing %/Ar
4) Find the simplest mole ratio

Question 6

Concentration of liquids

Answer 6

n=cV