Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

physical chemistry 3.1 > 3.1.2 - amount of substance > Flashcards

3.1.2 - amount of substance Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Chemistry flashcards Periodic Table flashcards Chemistry 101 flashcards Organic Chemistry 101 flashcards
1
Q

how to convert from molar concentration to mass concentration?

A

mass concentration / Mr

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

define relative molecular mass (Mr)

A

the average mass of a molecule relative tot 1/12 of the mass of an atom of carbon-12

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

define relative atomic mass (Ar)

A

the weighted masses of all the isotopes of an element relative to 1/12 of the mass of an atom of carbon-12

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

define the mole of a substance

A

the amount of that substance that contains the same number of particles as there are atoms in 12g of carbon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

how to convert from m^3 to dm^3

A

m^3 X 1000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

how to convert from cm^3 to dm^3

A

cm^3 divided by 1000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

why must air bubbles be removed from burettes and pipettes?

A

presence of air bubbles means that the titre read will be a higher volume, as it seems like there is a higher volume in the burette/pipette

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

why must the connical flask be rinsed with distilled water?

A
  • gets all the reactants into the flaks to react
  • doesn’t affect the titre, as the moles stay the same
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

why must only 3 drops of indicator be added to the conical flask?

A
  • indicators are acids, so could increase the pH.
  • this could affect the titre value
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

why must burettes and pipettes be rinsed with appropriate solutions?

A
  • rinse equipment with whatever is going into them
  • this ensures no residue is left from other solution
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q
  • what is the molecular formulae
  • what is the empirical formulae
A
  • the actual number of each element in a compound (C8H18)
  • the simplest whole number ratio of atoms in each element in a compound (C4H9)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

describe how to calculate empirical formulae of a compound

A
  1. find mass of each element per 100g
  2. calculate moles (mass/Mr)
  3. divide by the smallest mole value to find the ratio
  4. write formula using ratio
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

state the ideal gas equation

A

pV = nRT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

state the values and units in the ideal gas equation

A
  • pressure (Pa)
  • volume (m^3)
  • number of moles
  • gas constant (8.31Jk -1 mol -1)
  • temperature (K)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how to convert cm^3 to m^3

A

cm^3 / 1X 10^6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how to convert °C to K

A

+ 273

17
Q

explain what is meant by a hydrous compound

A

compound that contains water molecules that are bonded into its crystalline structure

18
Q

how is a hydrous compound changed into an anhydrous compound ?

A

heated up

19
Q

explain what is meant by uncertainty

A

interval within which the true value can be expected to lie

20
Q
  • define resolution
  • state resolutions relationship with uncertainty
A
  • how small a instrument can measure
  • smaller resolution = lower uncertainty
21
Q

explain what must be done to the uncertainty when taking a measurement (e.g. from a burette)

A
  • multiply the uncertainty by 2
  • because 2 judgements must be read
22
Q

explain how to calculate uncertainty

A
  • half the smallest possible unit you can make
  • balances smallest unit = 0.01g
  • uncertainty = 0.01g / 2
  • uncertainty = +/- 0.005g
23
Q

state how to calculate percentage apparatus uncertainty

A

( uncertainty for piece of apparatus / measurement value ) x 100

24
Q

state how to calculate actual experiment percentage uncertainty

A

( difference between actual and recorded values / actual value ) x 100

25
Q

what does it mean if actual experiment % uncertainty is lower than % uncertainty for apparatus

A

the difference is due to apparatus

26
Q

what does it mean if actual experiment % uncertainty is larger than % uncertainty for apparatus

A

the difference is due to human error

27
Q

state 4 reasons why actual yield could be lower than theoretical yield

A
  • not recovering all of the product
  • impurities
  • side reactions occurring
  • reaction is incomplete (e.g. reversible reactions)
28
Q

state the equation for percentage yield

A

( actual yield / theoretical yield ) x 100

29
Q

state the equation for atom economy

A

( Mr of useful product / Mr of total products ) x 100

physical chemistry 3.1 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions