# Calculations

All the calculations with examples

5.0 / 5

Teacher recommended

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- Created by: Georgia 753
- Created on: 11-04-16 13:19

CalculationsWord Document 165.97 Kb

## Pages in this set

### Page 1

Calculations

~ Unit 1 and Unit 2 ~

Mass Spectrometry Calculation

(Abundance1x m/z + (Abundance

1) 2x m/z + (Abundance

2) 3x m/z3)

Total Abundance

Example 1

Find the relative atomic mass of iron using the following data:

54 56 57 58

Fe (5.8%) Fe (91.6%) Fe (2.2%) Fe (0.3%)…

~ Unit 1 and Unit 2 ~

Mass Spectrometry Calculation

(Abundance1x m/z + (Abundance

1) 2x m/z + (Abundance

2) 3x m/z3)

Total Abundance

Example 1

Find the relative atomic mass of iron using the following data:

54 56 57 58

Fe (5.8%) Fe (91.6%) Fe (2.2%) Fe (0.3%)…

### Page 2

Protons =6 Neutrons =9 Electrons =6

Moles and Avogadro's Constant

A mole is the number of particles, the number of moles can be calculated by using the following

equation/triangle. This can also be used to calculate the mass (in grams) and the Mr of a compound.

Avogadro's Constant

The definition…

Moles and Avogadro's Constant

A mole is the number of particles, the number of moles can be calculated by using the following

equation/triangle. This can also be used to calculate the mass (in grams) and the Mr of a compound.

Avogadro's Constant

The definition…

### Page 3

0.500 / 0.500 =

1.00 mol dm-3

Example 2

25cm3 of

0.1 mol dm-3 NaOH neutralised

18.5cm3 of HCl. Calculate the concentration of HCl

NaOH + HCl NaCl +H 2O

Moles NaOH: (25/1000) x 0.1

= 0.0025

Moles HCl: 0.0025

Concentration HCl: 0.0025 / (18.5/1000)

= 0.135 mol dm-3

Example…

1.00 mol dm-3

Example 2

25cm3 of

0.1 mol dm-3 NaOH neutralised

18.5cm3 of HCl. Calculate the concentration of HCl

NaOH + HCl NaCl +H 2O

Moles NaOH: (25/1000) x 0.1

= 0.0025

Moles HCl: 0.0025

Concentration HCl: 0.0025 / (18.5/1000)

= 0.135 mol dm-3

Example…

### Page 4

Mg

3N 2

Molecular Formula

The molecular formula is the total number of atoms of each element in each molecule of a substance

Example

Calculate the molecular formula of CHwhen the relative molecular mass is 78

1. Take the empirical formula and Mr that is given

EF: CH

Mr: 78…

3N 2

Molecular Formula

The molecular formula is the total number of atoms of each element in each molecule of a substance

Example

Calculate the molecular formula of CHwhen the relative molecular mass is 78

1. Take the empirical formula and Mr that is given

EF: CH

Mr: 78…

### Page 5

Amount of product (actual yield)

Theoretical Yield

Reasons for the Yield being under 100%

Reactant could be left on equipment

Unexpected reactions

Contaminated reactants or impurities in the reactants

The reaction is reversible

Atom Economy

This is the proportion of the products of a reaction compared to the desired products.…

Theoretical Yield

Reasons for the Yield being under 100%

Reactant could be left on equipment

Unexpected reactions

Contaminated reactants or impurities in the reactants

The reaction is reversible

Atom Economy

This is the proportion of the products of a reaction compared to the desired products.…

### Page 6

Q is the enthalpy change- KJ

m is the mass of water/solution

c is the specific heat capacity of water

T is the change in temperature

Example

Calculate the neutralisation enthalpy of 50cm3 of 1 mol dm-3

NaOH with 50cm3 of 1 mol dm-3 HCl and the temperature

change of…

m is the mass of water/solution

c is the specific heat capacity of water

T is the change in temperature

Example

Calculate the neutralisation enthalpy of 50cm3 of 1 mol dm-3

NaOH with 50cm3 of 1 mol dm-3 HCl and the temperature

change of…

### Page 7

H=

-75

Enthalpy of Combustion and Formation

This calculation uses both enthalpies of formation and combustion to find the H, the diagram below is used to break

the calculation down:

Example

Calculate the enthalpy of combustion of propane (C3H8 (g)) given the following enthalpy changes

Hc

C (s)= -393 H…

-75

Enthalpy of Combustion and Formation

This calculation uses both enthalpies of formation and combustion to find the H, the diagram below is used to break

the calculation down:

Example

Calculate the enthalpy of combustion of propane (C3H8 (g)) given the following enthalpy changes

Hc

C (s)= -393 H…

### Page 8

H = 76

Oxidation States

To calculate oxidation states you have to take into account the following `rules'

1. On simple ions the oxidation state is the charge on the ion

2. In elements the oxidation state is always 0

3. The total of all the oxidation states needs to…

Oxidation States

To calculate oxidation states you have to take into account the following `rules'

1. On simple ions the oxidation state is the charge on the ion

2. In elements the oxidation state is always 0

3. The total of all the oxidation states needs to…

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# Calculations

All the calculations with examples

5.0 / 5

Teacher recommended

- Created by: Georgia 753
- Created on: 11-04-16 13:19

CalculationsWord Document 165.97 Kb

## Pages in this set

### Page 1

Calculations

~ Unit 1 and Unit 2 ~

Mass Spectrometry Calculation

(Abundance1x m/z + (Abundance

1) 2x m/z + (Abundance

2) 3x m/z3)

Total Abundance

Example 1

Find the relative atomic mass of iron using the following data:

54 56 57 58

Fe (5.8%) Fe (91.6%) Fe (2.2%) Fe (0.3%)…

~ Unit 1 and Unit 2 ~

Mass Spectrometry Calculation

(Abundance1x m/z + (Abundance

1) 2x m/z + (Abundance

2) 3x m/z3)

Total Abundance

Example 1

Find the relative atomic mass of iron using the following data:

54 56 57 58

Fe (5.8%) Fe (91.6%) Fe (2.2%) Fe (0.3%)…

### Page 2

Protons =6 Neutrons =9 Electrons =6

Moles and Avogadro's Constant

A mole is the number of particles, the number of moles can be calculated by using the following

equation/triangle. This can also be used to calculate the mass (in grams) and the Mr of a compound.

Avogadro's Constant

The definition…

Moles and Avogadro's Constant

A mole is the number of particles, the number of moles can be calculated by using the following

equation/triangle. This can also be used to calculate the mass (in grams) and the Mr of a compound.

Avogadro's Constant

The definition…

### Page 3

0.500 / 0.500 =

1.00 mol dm-3

Example 2

25cm3 of

0.1 mol dm-3 NaOH neutralised

18.5cm3 of HCl. Calculate the concentration of HCl

NaOH + HCl NaCl +H 2O

Moles NaOH: (25/1000) x 0.1

= 0.0025

Moles HCl: 0.0025

Concentration HCl: 0.0025 / (18.5/1000)

= 0.135 mol dm-3

Example…

1.00 mol dm-3

Example 2

25cm3 of

0.1 mol dm-3 NaOH neutralised

18.5cm3 of HCl. Calculate the concentration of HCl

NaOH + HCl NaCl +H 2O

Moles NaOH: (25/1000) x 0.1

= 0.0025

Moles HCl: 0.0025

Concentration HCl: 0.0025 / (18.5/1000)

= 0.135 mol dm-3

Example…

### Page 4

Mg

3N 2

Molecular Formula

The molecular formula is the total number of atoms of each element in each molecule of a substance

Example

Calculate the molecular formula of CHwhen the relative molecular mass is 78

1. Take the empirical formula and Mr that is given

EF: CH

Mr: 78…

3N 2

Molecular Formula

The molecular formula is the total number of atoms of each element in each molecule of a substance

Example

Calculate the molecular formula of CHwhen the relative molecular mass is 78

1. Take the empirical formula and Mr that is given

EF: CH

Mr: 78…

### Page 5

Amount of product (actual yield)

Theoretical Yield

Reasons for the Yield being under 100%

Reactant could be left on equipment

Unexpected reactions

Contaminated reactants or impurities in the reactants

The reaction is reversible

Atom Economy

This is the proportion of the products of a reaction compared to the desired products.…

Theoretical Yield

Reasons for the Yield being under 100%

Reactant could be left on equipment

Unexpected reactions

Contaminated reactants or impurities in the reactants

The reaction is reversible

Atom Economy

This is the proportion of the products of a reaction compared to the desired products.…

### Page 6

Q is the enthalpy change- KJ

m is the mass of water/solution

c is the specific heat capacity of water

T is the change in temperature

Example

Calculate the neutralisation enthalpy of 50cm3 of 1 mol dm-3

NaOH with 50cm3 of 1 mol dm-3 HCl and the temperature

change of…

m is the mass of water/solution

c is the specific heat capacity of water

T is the change in temperature

Example

Calculate the neutralisation enthalpy of 50cm3 of 1 mol dm-3

NaOH with 50cm3 of 1 mol dm-3 HCl and the temperature

change of…

### Page 7

H=

-75

Enthalpy of Combustion and Formation

This calculation uses both enthalpies of formation and combustion to find the H, the diagram below is used to break

the calculation down:

Example

Calculate the enthalpy of combustion of propane (C3H8 (g)) given the following enthalpy changes

Hc

C (s)= -393 H…

-75

Enthalpy of Combustion and Formation

This calculation uses both enthalpies of formation and combustion to find the H, the diagram below is used to break

the calculation down:

Example

Calculate the enthalpy of combustion of propane (C3H8 (g)) given the following enthalpy changes

Hc

C (s)= -393 H…

### Page 8

H = 76

Oxidation States

To calculate oxidation states you have to take into account the following `rules'

1. On simple ions the oxidation state is the charge on the ion

2. In elements the oxidation state is always 0

3. The total of all the oxidation states needs to…

Oxidation States

To calculate oxidation states you have to take into account the following `rules'

1. On simple ions the oxidation state is the charge on the ion

2. In elements the oxidation state is always 0

3. The total of all the oxidation states needs to…

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## Similar Chemistry resources:

3.0 / 5

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4.5 / 5

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