Chapter 3 Amount of Substances

Question 1

what is the mole equation for solids and liquids

Answer 1

moles (mol) = mass (g) / Mr

Question 2

what is the concentration equation for substances

Answer 2

concentration (moldm^-3) = moles (mol) / Volume (dm^3)

Question 3

what is the moles equation for gases at RTP

Answer 3

moles (mol) = Volume (dm^3) / molar gas volume (24dm^3)

Question 4

what is the gas equation

Answer 4

Pressure (Pa) x Volume (m^3) = moles (mol) x Gas Constant (8.314) x Temperature (K)

Question 5

what is the percentage yield equation

Answer 5

Percentage Yield = (Actual Yield / Theoretical Yield) x 100

Question 6

what is the Atom Economy equation

Answer 6

(molar mass of desired products / molar mass of all products) x 100

Question 7

What is Avogadro’s Number

Answer 7

6.02 x 10^23

Question 8

What is Avogadro’s Number (definition)

Answer 8

a number that is used to scale up to find moles

Question 9

How many atoms are in one mole of an element

Answer 9

6.02 x 10^23 atoms

Question 10

What is a mole

Answer 10

A unit that measures amounts in terms of number of atoms

Question 11

What is Ar

Answer 11

Relative atomic mass

Question 12

What is Mr

Answer 12

Relative Molecular mass

Question 13

what is the empirical formula

Answer 13

the formula of a molecule in its simplest ratio C1H3

Question 14

what is the molecular formula

Answer 14

the formula of a molecule in its actual ratio C2H6

Question 15

how much is 1dm in cm

Answer 15

10cm

Question 16

how much is 1dm^3 in cm^3

Answer 16

1000cm^3

Question 17

How do you convert from Celsius to Kelvin

Answer 17

take you Celsius reading and add 273. You should never have a negative Kelvin reading

Question 18

how do you calculate % difference for experiments

Answer 18

% difference = [(actual - expected) / Actual] x 100

Question 19

how do you calculate % error for experiments

Answer 19

% error = (error / reading) x 100

Question 20

what is a procedural error

Answer 20

an error in what you did during the experiment or in the method

Question 21

what is a precision error

Answer 21

an error in the equipment

Question 22

what are the three Ideal gas laws

Answer 22

> Size/volume of the gaseous atoms are negligible
No attraction between the atoms
Not at low temperature and high pressure conditions

Question 23

what is Room Temperature

Answer 23

20 C

Question 24

what is Room Pressure

Answer 24

101 KPa

Question 25

what is the RTP rule for gases

Answer 25

1 mole of any gas at RTP occupies a volume of 24dm^3

Question 26

what are the 3 characteristics of reactions with high Atom Economy

Answer 26

> Large proportion of desired products
Low proportion of waste products
Important for sustainability as they make best use of natural resources

Question 27

how do you work out Percentage Yield

Answer 27

work out the moles of each substance then compare to theoretical yield

Question 28

what is a Limiting Reagent

Answer 28

The reactant that is not in excess and is the first to be completely used up during the reaction