1.2 Amounts of Substance Flashcards

1
Q

Relative atomic mass (Ar)

A

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

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

Relative molecular mass (Mr)

A

The mass of a molecule of the compound relative to 1/12th 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

What is relative formula mass used for?

A

Ionic compounds

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

What is relative molecular mass used for?

A

Covalent substances

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

Relative formula mass (Mr)

A

The mass of one formula unit of an ionic compound relative to 1/12th the mass of an atom of carbon-12

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

A mole

A

The amount of substance that contains as many particles as there are in exactly 12g of carbon-12

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

What is the symbol for the Avagadro Constant?

A

L

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

What are the units of the Avagadro constant?

A

Mol⁻¹

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

What is the mass of one mole of a substance?

A

It’s Mr in grams.
E.g. 1 mole of carbon = 12.0g

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

Conversion of mg to g

A

×10⁻³

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

Conversion of kg to g

A

×10³

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Conversion of tonnes to g

A

×10⁶

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

Conversion of cm³ to dm³

A

×10⁻³

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

Equation for number of moles

A

Mass (in g) / Mr

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

Equation for number of atoms

A

n (moles) x L (Avogadro’s constant)

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

Equation for concentration

A

n (moles) / volume (dm³)

17
Q

Ideal gas equation

18
Q

Units used for the ideal gas equation

A

P = Pa
V = m³
n = mol
R = JK⁻¹mol⁻¹
T = Kelvin

19
Q

Empirical formula

A

The simplest whole number ratio of atoms of each element in a compound

20
Q

Molecular formula

A

The actual number of atoms of each element present in a molecule

21
Q

Conversion from degrees C to Kelvin

22
Q

What are the units of molar mass?

A

g mol⁻¹

23
Q

What 2 assumptions are made when using the ideal gas equation?

A
  1. No intermolecular forces between molecules
  2. Volume occupied by molecules in negligible relative to the volume of the container
24
Q

What are two acid-base indicators?

A

Methyl orange
Phenolphthalein

25
Percentage error
(Uncertainty / value) ×100
26
Methyl orange colour in acid
Red
27
Methyl orange colour in base
Yellow
28
Phenolphthalein colour in acid
Colourless
29
Phenolphthalein colour in base
Pink
30
Atom econemy
(Molecular mass (Mr) of desired product/sum of molecular masses of all products) ×100
31
Reasons for low percentage yeild
- Incompleate/reversible reactions - Side reactions - Mechanical losses - Impurities in the reactants
32
What is a back titration?
A titration used for substances that are insoluble in water. They are instead reacted with acid to form a solution.
33
Water of crystallisation
The water molecules that form an essential part of the crystalline structure of a hydrated salt