Section 2 - Amount of Substance

Question 1

What is the formula for converting between particles and moles?

Answer 1

Number of particles = Number of moles x Avogadro’s constant

Question 2

What are the two formulas for calculating moles?

Answer 2

Moles = mass of substance/Mr or concentration(mol dm^-3) x volume(dm^3)

Question 3

How do you convert from cm^3 to dm^3?

Answer 3

Divide by 1000.

Question 4

What is the ideal gas equation?

Answer 4

pV=nRT

Question 5

What is the unit for pressure when using the ideal gas equation?

Answer 5

Pa

Question 6

What is the unit for volume when using the ideal gas equation?

Answer 6

m^3

Question 7

What is the unit for temperature when using the ideal gas equation?

Answer 7

K

Question 8

How do you convert from degrees Celsius to Kelvin?

Answer 8

+273

Question 9

How many m^3 are in 1cm^3?

Answer 9

1 x 10^-6

Question 10

How many m^3 are in 1dm^3?

Answer 10

1 x 10^-3

Question 11

Define Empirical Formula

Answer 11

The simplest whole number ratio of atoms of each element in a compound.

Question 12

Define Molecular Formula

Answer 12

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

Question 13

What is the formula for calculating Percentage Yield?

Answer 13

Actual Yield/Theoretical Yield x 100

Question 14

Why is actual yield less than theoretical yield?

Answer 14

• Not all reactants react

- Some chemicals are lost (eg. on filter paper/during transfers)

Question 15

What is Atom Economy?

Answer 15

A measure of the proportion of reactant atoms that become part of the desired product in the balanced chemical equation.

Question 16

What is the formula for Atom Economy?

Answer 16

Mr of desired product/sum of Mr of all reactants x 100