Amount Of Substance

Question 1

What does amount of substance mean?

Answer 1

The quantity whose unit is the mole

Question 2

What does mole mean?

Answer 2

Amount of any substance containing as many particles as there carbon atoms in exactly 12g of carbon-12 isotope

Question 3

What does the Avogadro constant mean?

Answer 3

The number of atoms of the carbon-12 isotope (6.02 * 10 to the 23)

Question 4

What does molar mass mean?

Answer 4

Mass per mole of a substance measured by grams per mole

Question 5

What does molar volume mean?

Answer 5

Volume per mole of a gas measured by mole per decimetre cubed

Question 6

What does empirical formula mean?

Answer 6

Simplest whole number ratio of atoms of each element present in a compound

Question 7

What does molecular formula mean?

Answer 7

Actual number of atoms of each element in a molecule

Question 8

What does hydrated mean?

Answer 8

Refers to a crystalline compound containing water molecules

Question 9

What does anhydrous mean?

Answer 9

Refers to a substance that contains no water molecules

Question 10

What does water of crystallisation mean?

Answer 10

Refers to water molecules that form an essential part of the crystalline structure of a compound

Question 11

What does concentration mean?

Answer 11

Amount of solute in moles dissolved in one decimetre cubed of solution

Question 12

What is the ideal gas equation?

Answer 12

pV = nRT

Question 13

What is p?

Answer 13

Pressure

Question 14

What is P measured in?

Answer 14

Pa

Question 15

How do you convert KPa to Pa?

Answer 15

Multiply by 1000

Question 16

What is V?

Answer 16

Volume

Question 17

What is V measured in?

Answer 17

Metres cubed

Question 18

How do you convert from centimetre cubed to metre cubed?

Answer 18

Divide by 1,000,000

Question 19

How do you convert from decimetre cubed to metre cubed?

Answer 19

Divide by 1,000

Question 20

What is n?

Answer 20

Number of moles

Question 21

What is R?

Answer 21

The ideal gas constant

Question 22

What is T?

Answer 22

Temperature

Question 23

How do you convert from degrees Celsius to kelvin?

Answer 23

+ 273k

Question 24

What is temperature measured in?

Answer 24

Kelvin

Question 25

When do we use the ideal gas equation?

Answer 25

When it is not room temperature and pressure

Question 26

Why is 100% percentage yield very difficult to achieve?

Answer 26

1) Reversible reaction
2) Reactants may contain impurities
3) By-products may be formed from unexpected reactions
4) Reactants/products may be left in apparatus during the experiment
5) Product may be lost during separation and purification, such as being soaked onto filter paper

Question 27

How do you calculate percentage yield?

Answer 27

Actual amount over theoretical amount of product in terms of moles or mass times by 100

Question 28

What is atom economy?

Answer 28

Considers the efficiency of a reaction by looking at the proportion of the products formed that are actually used

Question 29

Why are reactions with high atom economies so important?

Answer 29

They make better use of finite resources and reduce the need to process and safely dispose of waste products

Question 30

How do you calculate atom economy?

Answer 30

Molecular mass of desired product over the sum of the molecular masses of all products times by 100