Amount Of Substance

Question 1

What is the Avogadro constant?

Answer 1

The number of atoms in12g of carbon-12

Question 2

Using mass and Mr, how can you work out the no. of moles?

Answer 2

No. of moles = mass(g)/mass of 1mole

Question 3

How do you work out the number of moles in a given volume of a solution?

Answer 3

Number of moles in solution= (conc (mol dm-3) X volume (dm3)

Question 4

What is 100 Pa in Nm-2?

Answer 4

100Nm-2

Question 5

Using the ideal gas equation, what is the general equation for volume?

Answer 5

V=nRT/P

Question 6

Using the empirical formula of a substance, how would you work out its molecular formula?

Answer 6

Work out the Mr of the group of atoms from the empirical formula you just worked out, then divide this the actual Mr of the substance. This then tells you how many units of the empirical formula used earlier is actually in the substance.

Question 7

What is the general equation for atom economy?

Answer 7

% atom economy = (Mr of desired product/total Mr of reactants) X 100

Question 8

What does yield tell us?

Answer 8

The efficient off the process.

Question 9

What is the value of the Avogadro constant?

Answer 9

6.022 x 10(to the power of 23)

Question 10

Rearrange T to make it the subject of the ideal gas equation.

Answer 10

T= Pv/nR