1.2 - Amount of Substance

Question 1

Define Relative Molecular Mass

Answer 1

The average mass of a molecule relative to one twelfth of the mass of an atom of carbon-12.

Question 2

Define Relative Atomic Mass

Answer 2

The average mass of an atom of an element relative to one twelfth of the mass of an atom of carbon-12.

Question 3

Define the Avogadro Constant

Answer 3

Number of particles/atoms/ions in one mole of a substance.

Question 4

The equation that links mass of 1 mol, mass of 1 atom and Avogadro constant.

Answer 4

Mass of 1 mol = mass of 1 atom x Avogadro constant

Question 5

Define percentage yield.

Answer 5

The % of a product produced by a reaction, compared to a theoretical maximum.

Question 6

How would you calculate percentage yield?

Answer 6

Mass of useful product / expected mass of useful product.

Question 7

What can the percentage yield of a practical be used to investigate?

Answer 7

Efficiency of practical techniques and whether reactions proceed as expected.

Question 8

Define atom economy.

Answer 8

% of amount of reactants made into certain (useful) products.

Question 9

How would you calculate atom economy?

Answer 9

Mr of atoms of useful products/ Mr of atoms of reactants.

Question 10

What can the atom economy of a reaction be used to investigate?

Answer 10

Efficiency of using a specific reaction to produce a product.

Question 11

What is the Ideal Gas Equation?

Answer 11

pV = nRT
Pressure (Pa) x Volume (m^3) = number of moles x gas constant (8.31) x temperature (K)

Question 12

What are the standard conditions?

Answer 12

25*C/298K
1 atm/ 100kPa

Question 13

How do you convert *C to K?

Answer 13

+273

Question 14

Define Empirical Formula

Answer 14

Simplest whole number ratio of atoms in a compound.

Question 15

What is the equation that links moles, concentration and volume?

Answer 15

Moles = concentration x volume

Question 16

What is the equation that links moles, mass and Mr?

Answer 16

Moles = mass/Mr