Amount of substance Flashcards

1
Q

What is the water of crystallisation?

A
  • Water molecules existing within the crystal structures
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is Avogadro’s constant ?

A
  • number of particles per moles
    6.02 x 10^23
    n = particles / AG
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How to calculate water of crystallisation?

A
  • calculate the mass of water + anhydrous salt
  • work out the moles of both
  • find the smallest whole number ratio
  • n(salt) : n(H2O)
  • value of n(H20) is the value in the formula.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How to calculate moles from mass?

A

n = mass (g) / Mr

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

How to calculate moles from conc?

A

n = C (moldm) x V (dm3)
or
n = C x V(cm3)x10-3

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

What is the ideal gas equation?

A

pV = nRT

p = Pa 
V = m3
n = mol
R = 8.31
T = K
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Ideal gas equation conversion units?

cm3
dm3
C
kPa

A

cm3 to m3 = x10^-6
dm3 to m3 = x10^-3
C to K = +273
kPa to Pa = x10^3

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

what are standard conditions?

A

298K

100kPa

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

How to calculate percentage yield?

A

Actual yield / theoretical yield X 100

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

why is yield never 100%

A
  • reaction wasn’t completed
  • side reactions
  • loss of product during purification
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is atom economy and how to calculate it?

A

Mr of desired product / Mr of all products X 100

  • how efficient a reaction is.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the importance of atom economy

A
  • HAE means raw materials are used more efficiently ; more sustainable
  • HAE means less by-products so less time + money spent separating these from desired product
  • HAE produce less waste ; benefits environment.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Assumptions in the experimental formula of a hydrated salt?

A
  • all water has been lost : heat to constant mass

- no further decomposition ; salts decompose further when heated (difficult to tell bc no colour change)

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

cm3 to ml

A

1cm3 = 1ml

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

dm3 to cm3 to ml to L

A

1dm3 = 1000cm3 = 1000ml = 1L

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

kg to tonnes

A

1000kg = 1 tonne

17
Q

mg to g

A

1000mg = 1 gram