Brainscape's Knowledge GenomeTM

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


See full index

Paper 1 CHEM MMS EXAM > ✅5 - Formulae, Equations and Amounts of Substance > Flashcards

✅5 - Formulae, Equations and Amounts 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

What are amounts of substance measured in?

A

Moles (mol)

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

What does one mole contain?

A

A standard number of atoms, molecules or ions

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

What is the relative atom mass?

A

The average mass d an element relative to 1/12th if the mass of an atom of carbon12.

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

What is molar mass (Mr)?

A

The mass of one mole of a chemical with the unit g mol-1.

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

How would you work out the molar mass of a molecule?

A

Add up the relative atomic masses of all the atoms in the molecule

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

How do you work out the amount of substance in moles?

A

mass/ Mr

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

What is a species?

A

A collective noun to refer generally to atoms, molecules or ions

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

What is the Avogadro constant?

A

The number of atoms, molecules or ions in one mole of a substance. 6.02 x 10^23 mol-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How would you work out the number of particles?

A

n x Avogadro

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the empirical formula?

A

The simplest whole number ratio of the atoms of different elements in a compound

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How would you work out the empirical formula?

A
  1. Write down the actual mass of each element
  2. Write down the molar mass of each element
  3. Divide the actual mass by the molar mass for each element
  4. Divide all the numbers by the smallest one
  5. See ratio
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is molecular formula?

A

The total number of atoms of each element in the molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is percentage composition?

A

The percentage by mass of each of the elements in a sample of a compound

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

How would you work out the empirical formula from percentages?

A

Turn each percentage into grams and assume the total mass of the compound is 100g

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the ideal gas equation?

A

pV = nRT

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

1 atmosphere =

A

100,000 Pa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

1 bar =

A

100k Pa (100,000Pa)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

To convert °C into K…

A

… +273 to the number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

To convert K into °C

A

Take away 273 from the number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

1m^3 =

A

1000dm^3 (1,000,000cm^3)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

R=

A

8.31JK-1mol-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What most the units be in the ideal gas equation?

A 
P = Pa
V = m^3
n = moles
T = Kelvin
23
Q

The gas laws state that the volume of a gas depends on what three things?

A
  • The temperature
  • The pressure
  • The amount of gas in moles
24
Q

What could the ideal gas equation be used for?

A

Measuring the molar masses of gases in the days before mass spectrometry

25
Q

What is the ideal gas equation accurate enough to determine?

A

The molecular formula of elements and compounds

26
Q

How is the molecular formula found from the ideal gas equation?

A
  • A weighted sample of a liquid is injected into a syringe heated in an oven
  • Measurements are taken of the volume of vapour, the temperature and its pressure
  • They are then converted into SI units and put into the ideal gas equation to find the number of moles
27
Q

What is the molar volume of a gas?

A

The volume of 1mol of the gas under stated conditions. At room temperature and atmospheric pressure the molar volume of all gases is 24dm-3mol-1

28
Q

What is room temperature?

A

25°C

29
Q

What is atmospheric pressure?

A

100kPa

30
Q

Volume of gas (dm3) =

A

n x 24

31
Q

How would led you calculate the amounts of reactants and products?

A
  • Write the balanced equation for the reaction
  • Write down the amount in moles of the relevant reactants and products according to the ratio in the equation
  • Convert the amount in moles into masses of the reactants and products
  • Scale the masses to the quantities required
32
Q

The volume of gas, under a given temperature and pressure depends only on…

A

…the amount of gas, not the type of gas

33
Q

Concentration (g/dm-3) =

A

Mass of solute (g) / volume of solution (dm-3)

34
Q

Concentration (mol/dm-3) =

A

n / volume (dm3)

35
Q

What is the concentration of a solution?

A

How much solute is dissolved in a certain volume

36
Q

What is a titration?

A

A volumetric analysis technique for finding the concentrations of solutions and for investigation the amounts of chemicals involved in reactions

37
Q

What is a standard solution?

A

A solution with an accurately known concentration

38
Q

What is a primary standard?

A

A chemical with can be weighed out accurately to make up a standard solution

39
Q

The method for preparing a standard solution is only appropriate with a chemical that is…

A
  • is very pure
  • does not gain or loss mass when in the air
  • has a relatively high molar mass so that weighing errors are minimised
40
Q

What was the ideal gas equation used for?

A

Measuring the molar masses of gases before mass spectrometry

41
Q

What is the ideal gas equation accurate enough to determine?

A

The molecular formula of elements and compounds

42
Q

What does the ideal gas equation show?

A

That at a fixed temperature and pressure the volume of a gas depends only
on the amount of moles.

43
Q

How do you calculate the masses of reactants and products?

A
  1. Write a balanced equation
  2. Write down the amounts in moles of the relevant reactants and products in the equation
  3. Convert these amounts in moles of the relevant reactants and products into masses
  4. Scale to the quantities required
44
Q

What is an uncertainty?

A

The amount of error your measurements might have?

45
Q

For any piece of equipment, what will the uncertainty be?

A

Half the smallest increment of measure in either direction

46
Q

What should be done if different measurements are being combined?

A

Their uncertainties should be combined

47
Q

How would you calculate percentage uncertainty?

A

(Uncertainty/reading) x 100

48
Q

How can uncertainty be reduced?

A

By using the most precise equipment possible and the largest measurements

49
Q

What is theoretical yield?

A

The maximum that you could get

50
Q

How would you calculate theoretical yield?

A

Using the moles of reactants and products

51
Q

How would you calculate percentage yield?

A

Actual yield/theoretical yield x 100

52
Q

What is atom economy?

A

A measure of how efficient the reaction is

53
Q

How would you calculate atom economy?

A

Molar mass of desired product/combined molar masses of all products x 100

ALL X STOICHIOMETRY

Paper 1 CHEM MMS EXAM (12 decks)

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