Chapter 7: Mole Concept and Stoichiometetry

Question 1

How many particles does one mole of a substance contain?

Answer 1

6 x 10^23

Question 2

What is the volume of one mole of a gas molecule?

Answer 2

24 dm^3 at room temperature pressure (r.t.p.)

Question 3

How many cm^3 is 1 dm^3?

Answer 3

1 dm^3 = 1000 cm^3

Question 4

How many g is in 1 tonne?

Answer 4

1 tonne = 1 x 10^6g

Question 5

What are the conversions between mass and mole?

Answer 5

Mass/molar mass = no. of moles
Mole x molar mass = no. of moles

Question 6

What are the conversions between number of particles and mole?

Answer 6

No. of particles/6 x 10^23 = no. of moles
No. of moles x 6 x 10^23 = no. of particles

Question 7

What are the conversions between volume of gas and mole?

Answer 7

Vol. of gas/24 dm^3 or 24 000 cm^3 = no. of moles
No. of moles x 24 dm^3 or 24 000 cm^3 = vol. of gas

Question 8

What are the conversions between the concentration of a solution in mol/dm^3 and g/dm^3?

Answer 8

Concentration in mol/dm^3 x molar mass = concentration in g/dm^3
Concentration in g/dm^3/molar mass = concentration in mol/dm^3
(Refer back to conversions between moles and mass)

Question 9

What is the limiting reagent?

Answer 9

It is the reactant that is completely used up in the reaction, while the other reagents not used up are the excess.

Question 10

What is the formula for the concentration of a solution?

Answer 10

No. of moles/volume (dm^3) = concentration in mol/dm^3