The mole

Question 1

Define amount of substance

Answer 1

The quantity whose unit of the mole, used as a means of counting any species such as atoms, ions, and molecules

Question 2

Define mole

Answer 2

The amount of substance containing as many elementary particles as there are carbon atoms in exactly 12g of the carbon-12

Question 3

Define Avogadro’s constant

Answer 3

The number of atoms per mole of the carbon-12 isotope

Question 4

Define Molar Mass

Answer 4

The mass per mole of a substance

Question 5

What are the units for molar mass?

Answer 5

g per mole

Question 6

Define empirical formula

Answer 6

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

Question 7

Define molecular formula

Answer 7

The actual number of each element present in a molecule

Question 8

Define anhydrous

Answer 8

containing no water molecules

Question 9

Define hydrated

Answer 9

A crystalline compound containing water molecules

Question 10

Define water of crystallisation

Answer 10

Water molecules that are bonded into the crystalline structure of a compound

Question 11

What does EMMA stand for?

Answer 11

Equation
Moles known
Moles wanted
Answer

Question 12

Define concentration

Answer 12

The amount of solute in mol dissolved per dm3 of solution

Question 13

Using volume, how can moles be calculated?

Answer 13

no. moles = concentration x volume

Question 14

Give a suitable indicator for titration reactions

Answer 14

Phenolphthalein

Question 15

What is the molar gas volume at RTP?

Answer 15

24.0 dm3 per mol

Question 16

How can the no. particles be calculated?

Answer 16

No. mol x Avogadro constant

Question 17

Define standard solution

Answer 17

A solution whose exact concentration is known

Question 18

Give the formula for calculating concentration

Answer 18

c=n/v

Question 19

Which piece of equipment is used to make up a standard solution?

Answer 19

A volumetric flask

Question 20

How are burettes read?

Answer 20

to the nearest half division

Question 21

Why do you repeat your titration until you get concordant results?

Answer 21

To ensure with confidence that the exact drop which changes the indicator’s colour is found

Question 22

What should a titration begin with?

Answer 22

A rough titration

Question 23

Why are rough titrations carried out?

Answer 23

To give you a rough idea of the volume of solution which changes the indicator colour

Question 24

Are rough titrations included in titration calculations?

Answer 24

No

Question 25

How do you calculate volume of a gas at rtp?

Answer 25

No. mols x molar gas volume

Question 26

What is molar gas volume?

Answer 26

The volume per mole of gas molecules at a stated temperature and pressure

Question 27

What conditions make rtp?

Answer 27

• about 20 degrees Celsius

- 101 KPa or 1 atm of pressure

Question 28

What is the ideal gas law?

Answer 28

pV= nRT

Question 29

In the ideal gas law what is pressure measured in?

Answer 29

pascals

Question 30

In the ideal gas law what units are used for volume?

Answer 30

m cubed

Question 31

In the ideal gas law what units are used for temperature?

Answer 31

K (kelvin)

Question 32

What is the gas constant?

Answer 32

8.314

Question 33

What are the units for the ideal gas constant?

Answer 33

pascals per m cubed per kelvin per mol

Question 34

How do you convert between Celcius and kelvin?

Answer 34

+273

Question 35

How do you convert from dm cubed to m cubed?

Answer 35

/1000

Question 36

How do you convert from kPa to Pa?

Answer 36

x 1000

Question 37

What is the number of atoms in one mol of carbon dioxide?

Answer 37

1.8 x 10 to the 24

There are 3 atoms in CO2 and therefore avogadro constant should be multiplied by 3

Question 38

How can random error in a titration be reduced?

Answer 38

• repeat titration until concordant results are achieved

- calculate a mean from the concordant results