Amount of substance

Question 1

What is the formula and charge on Sulfate

Answer 1

Sulfate SO42-

Question 2

What is the formula and charge on Nitrate

Answer 2

Nitrate NO3-

Question 3

What is the formula and charge on Carbonate

Answer 3

Carbonate CO32-

Question 4

What is the formula and charge on Hydroxide

Answer 4

Hydroxide OH-

Question 5

What is the formula and charge on Ammonium

Answer 5

Ammonium NH4+

Question 6

What is the formula of Water

Answer 6

Water H2O

Question 7

What is the formula of Methane

Answer 7

Methane CH4

Question 8

What is the formula of Ammonia

Answer 8

Ammonia NH3

Question 9

What is the formula of Hydrogen peroxide

Answer 9

Hydrogen peroxide H2O2

Question 10

What is meant by empirical formula

Answer 10

Empirical formula – the simplest whole number ratio of the atoms of each element in a compound.

Question 11

What is meant by molecular formula

Answer 11

Molecular formula – the actual number of atoms of each element in one molecule of the substance.

Question 12

What is meant by ionic equation.

Answer 12

Ionic equation – shows only the substances (can be covalent) taking part and being made in the reaction.

Question 13

What is meant by spectator ions

Answer 13

Spectator ions - Ions which do not take part in the reaction.

Question 14

What is meant by the mole

Answer 14

The mole – the amount of a substance that contains the number of particles equal to the Avogadro constant.

Question 15

What is meant by relative formula mass RFM

Answer 15

Relative formula mass RFM– The total of the relative molecular mass (Mr).

Question 16

What is meant by molar mass

Answer 16

Molar mass – the mass of 1 mole.

Question 17

What is meant by avogadro constant

Answer 17

Avogadro constant – the number of particles in one mole.

Question 18

What is meant by theoretical yield

Answer 18

Theoretical yield – The amount in moles or mass you would expect to be produced if the reaction goes to completion.

Question 19

What is meant by actual yield

Answer 19

Actual yield – The amount in moles or mass you obtain experimentally.

Question 20

What is meant by standard solution

Answer 20

Standard solution – a solution of a known concentration.

Question 21

Why you don’t get 100% yield

Answer 21

Loss from transferring between containers

Question 22

How do you calculate empirical formula

Answer 22

Write out the mass of the elements.

Question 23

How do you do a reacting mass calculation?

Answer 23

1. Calculate the number of moles by dividing the mass by the Mr.

Question 24

How do you make a standard solution?

Answer 24

Weigh out accurately the mass of your solid.

Question 25

How do you do a titration?

Answer 25

Rinse equipment with deionised water then the solution you will be filling it with.  

Question 26

How do you do a back titration?

Answer 26

React a insoluble solid e.g. Group II oxide, carbonate etc with known volume of excess hydrochloric acid.  

Question 27

How do you calculate % error?

Answer 27

Error / reading x 100.

Question 28

What colour is Phenolphthalein in acidic solutions

Answer 28

colourless

Question 29

What colour is Phenolphthalein in alkaline solutions

Answer 29

pink

Question 30

What colour is Methyl orange in acidic solutions

Answer 30

Red

Question 31

What colour is Methyl orange in alkaline solutions

Answer 31

Yellow

Question 32

Which titrations are Phenolphthalein suitable for?

Answer 32

Strong acid – strong base

Question 33

Which titrations are Methyl orange suitable for?

Answer 33

Strong acid- strong base

Question 34

How do you work out the number of moles of a solid?

Answer 34

Number of moles = mass / molecular mass

Question 35

How do you work out the number of moles of a liquid?

Answer 35

Number of moles = volumes x concentration

Question 36

How do you work out the number of moles of a solid?

Answer 36

Number of moles = volume / 24dm3

Question 37

How can you calculate number of moles using Avogadro’s number?

Answer 37

Amount (in moles) = number of particles / Avogadro constant

Question 38

How do you calculate % yield?

Answer 38

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

Question 39

How do you calculate atom economy?

Answer 39

Atom economy = Relative formula mass of desired products / relative formula mass of all products X 100

Question 40

What is the ideal gas equation?

Answer 40

pV=nRT

Question 41

What are the units in the ideal gas equation?

Answer 41

P=pressure (Pa) (NOT kPa)

Question 42

What is the number for the Avogadro’s constant?

Answer 42

The Avogadro constant (L) = 6.02x1023