Amount Of Substance

Question 1

Mole definition

Answer 1

The amount of substance in grams that has the same number of particles as there are atoms in 12 grams of carbon-12

Question 2

Molar gas volume definition

Answer 2

The volume of 1 mole of a gas at a given temperature and pressure. All gases have this same volume.

Question 3

Molar gas volume in standard conditions

Answer 3

24dm3

Question 4

Avogadro’s constant definition

Answer 4

One mole of any specified entity contains 6.02 x 10^23 of that entity

Question 5

Empirical formula definition

Answer 5

The simplest ratio of atoms of each element in the compound

Question 6

Number of cm³ in 1dm³

Answer 6

1000

Question 7

Number of cm³ in 1m³

Answer 7

1000000

Question 8

Number of dm³ in 1m³

Answer 8

1000

Question 9

How to calculate dilutions

Answer 9

New diluted concentration = original concentration x (original volume / new diluted volume)

Question 10

Ideal gas equation

Answer 10

PV = nRT
P: Pa
V: m³
T: K
n: moles
R: 8.31

Question 11

Potential errors in using a gas syringe

Answer 11

• gas escapes before bung inserted
• syringe sticks
• some gases like carbon dioxide or sulfur dioxide are soluble in water so the true amount of gas is not measured

Question 12

Changing gas conditions equation

Answer 12

P1V1 = P2V2
T1 T2

Question 13

How to calculate number of particles

Answer 13

Number of particles = moles of substance x avogadro’s constant

Question 14

Percentage yield equation

Answer 14

Percentage yield = (actual yield / theoretical yield) x 100

Question 15

How can percentage yield end up being lower?

Answer 15

• incomplete reactions
• side reactions
• losses during transfers of substances
• losses during purification stages

Question 16

Atom economy equation

Answer 16

Atom economy = (mass of useful products / mass of all reactants) × 100

Question 17

How do you calculate empirical formula?

Answer 17

% composition over Mr then divide those values by the smallest of them to find the ratio