2: Amount of Substance

Question 1

What is the mole?

Answer 1

6.022 x 10^23 particles - these could be anything, including ions, electrons, molecules etc

Question 2

Give the equation to calculate number of particles.

Answer 2

Number of particles = Moles x Avogadro constant

Question 3

Give the formula for calculating moles.

Answer 3

Moles = mass / Mr

Question 4

Give the formula for calculating moles using volume.

Answer 4

Moles = concentration x (volume/1000)

Question 5

State the ideal gas equation.

Answer 5

pV = nRT

Question 6

Rearrange the ideal gas equation for p.

Answer 6

p = nRT / V

Question 7

Rearrange the ideal gas equation for V.

Answer 7

V = nRT / p

Question 8

Rearrange the ideal gas equation for n.

Answer 8

n = pV / RT

Question 9

Rearrange the ideal gas equation for T.

Answer 9

T = pV / nR

Question 10

What is empirical formula?

Answer 10

The simplest ratio of elements in a compound.

Question 11

What is molecular formula?

Answer 11

The actual number of atoms of each element in a compound.

Question 12

Describe how to calculate empirical formula?

Answer 12

1. Divide the molecular mass of the element by the mass of it in the compound
2. Divide your answers from 1 by the smallest number of moles from 1
3. This creates a simple ratio of atoms

Question 13

Give the formula for percentage yield?

Answer 13

Actual yield / Theoretical yield (x100)

Question 14

What does atom economy measure?

Answer 14

The proportion of reactant atoms that become part of the desired product.

Question 15

What are 2 economic advantages of a high atom economy?

Answer 15

Less waste
Less raw materials required to make more of the desired product.

Question 16

Give 2 ethical/environmental advantages of high atom economy.

Answer 16

Less use of finite resources.
Less waste produce which could be damaging to the environment.

Question 17

Give the formula for atom economy.

Answer 17

Mr of Desired Product / Mr of all Products (x100)