3.1.3
Calculating Relative Formula Mass
Calculating the Relative Formula Mass (Mr)
Calculating the Relative Formula Mass (Mr)
To calculate the relative formula mass of a compound, we need to know the relative atomic masses (Ar) of the elements that make the compound. Then we multiply the Ar values by the number of atoms of that element in the compound. Then we add these numbers together.
E.g. hydrochloric acid (HCl)
E.g. hydrochloric acid (HCl)
- Identify the relative atomic mass (Ar) of each element in the compound:
- Ar of hydrogen = 1
- Ar of chlorine = 35.5
- So, the total Mr of HCl is 1 + 35.5 = 36.5
E.g. sulfuric acid (H2SO4)
E.g. sulfuric acid (H2SO4)
- Identify the relative atomic mass (Ar) of each element in the compound:
- Ar of hydrogen = 1
- Ar of sulfur = 32
- Ar of oxygen = 16
- So, the total Mr of H2SO4 is (2x1) + (1x32) + (4x16) = 98
1Atomic Structure
1.1Atoms & Elements
1.1.1Elements & Compounds
1.1.2Chemical Formula
1.1.3Chemical Reactions
1.1.4Chemical Equations
1.1.5Mixtures
1.1.6Separating Mixtures
1.1.7Separating Mixtures 2
1.1.8Model of the Atom
1.1.9Sub-Atomic Particles
1.1.10Atom Size
1.1.11Atomic Number
1.1.12Atomic Number - Calculations
1.1.13Isotopes
1.1.14Isotopes HyperLearning
1.1.15Isotopes - Calculations
1.1.16Relative Atomic Mass
1.1.17Electron Structure
1.1.18Periodic Table
1.1.19The History of the Periodic Table
1.1.20Metals & Non-Metals
1.1.21Noble Gases
1.1.22Displacement Reaction
1.1.23Halogens
1.1.24Alkali Metals
1.1.25Alkali Metals - Properties
1.1.26Transition Metals
1.1.27Transition Metals - Special Properties
1.1.28End of Topic Test - Atomic Structure
1.1.29Grade 9 - Atoms & Elements
1.1.30Exam-Style Questions - Atomic Structure
1.1.31Application Questions - Atomic Structure
2Chemical Bonding
2.1Chemical Bonds
2.2States of Matter
2.3Chemical Properties
2.3.1Ionic Compounds
2.3.2Chemical Properties of Ionic Compounds
2.3.3Small Molecules
2.3.4Chemical Properties of Small Molecules
2.3.5Molecular Forces - Polymers
2.3.6Molecular Forces - Polypropene
2.3.7Giant Covalent Structures
2.3.8Metals
2.3.9Alloys
2.3.10Conductors
2.3.11Carbon Structures - Diamond
2.3.12Carbon Structures - Graphite
2.3.13Carbon Structures - Graphene
2.3.14Carbon Structures - Fullerenes
2.3.15Carbon Structures - Summary
2.3.16Clumps
2.3.17Nanoparticles
2.3.18Nanotechnology
2.3.19Nanotechnology 2
2.3.20Surface Area to Volume Ratio
2.3.21Nanotechnology Uses
2.3.22End of Topic Test - Chemical Bonding
2.3.23Grade 9 - Bonding & Structure
2.3.24Exam-Style Questions - Allotropes of Carbon
3Quantitative Chemistry
3.1Chemical Measurements
3.1.1Conservation of Mass
3.1.2Relative Formula Mass
3.1.3Calculating Relative Formula Mass
3.1.4Relative Formula Mass - Calculations
3.1.5Changing Mass
3.1.6Measuring Mass
3.1.7Equations
3.1.8Empirical Formula
3.1.9Introducing Moles
3.1.10Relative Formula Mass
3.1.11Amounts of Substance
3.1.12Moles to Balance Equations
3.1.13Limiting Reactants
3.1.14Concentration of Solutions
3.1.15Moles - Calculations
3.1.16Percentage Yield
3.1.17Calculating Yield
3.1.18Percentage Yield - Calculations
3.1.19Moles & Yield
3.1.20Moles & Yield 2
3.1.21Atom Economy
3.1.22Reaction Pathway
3.1.23Atom Economy - Calculations
3.1.24Concentrations of Solute
3.1.25Calculating the Amount of Solute
3.1.26Amount of Substance in Relation to Volumes and Gas
3.1.27Concentrations & Amounts - Calculations
3.1.28Empirical Formula - Calculations
3.1.29End of Topic Test - Quant Chemistry
3.1.30Grade 9 - Quantitative Chemistry
3.1.31Exam-Style Questions - Moles
4Chemical Changes
4.1Acids, Alkalis & Redox Reactions
4.2Reactivity of Metals
4.3Reactions of Acids
4.3.1Reactions of Metals with Acids
4.3.2Redox Reactions
4.3.3Neutralisation of Acids
4.3.4Soluble Salts
4.3.5Required Practical: Separating Mixtures
4.3.6The pH Scale
4.3.7Numerical pH Scale
4.3.8Measuring pH
4.3.9Neutralisation & Titrations
4.3.10Neutralisation & Titrations 2
4.3.11Neutralisation & Titrations 3
4.3.12Neutralisation & Titrations 4
4.3.13Strong and Weak Acids
5Energy Changes
5.1Exothermic & Endothermic Reactions
6The Rate & Extent of Chemical Change
6.1Rate of Reaction
6.2Reversible Reactions
6.2.1Reversible Reactions
6.2.2Dynamic Equilibrium
6.2.3Conditions and Equilibrium
6.2.4Equilibrium Position - Temperature
6.2.5Equilibrium Position - Pressure
6.2.6Equilibrium Position - Concentration
6.2.7End of Topic Test - Rates of Reaction
6.2.8Grade 9 - Rate & Extent of Chemical Change
6.2.9Exam-Style Questions - Reversible Reactions
7Organic Chemistry
7.1Carbon Compounds
7.1.1Crude Oil
7.1.2Properties of Hydrocarbons
7.1.3Alkanes
7.1.4Smallest Alkanes
7.1.5Fractional Distillation
7.1.6Process of Fractional Distillation
7.1.7Homologous Series
7.1.8Burning Hydrocarbons
7.1.9Heavy Fractions of Crude Oil
7.1.10Cracking
7.1.11Uses of Alkenes
7.1.12Exam-Style Questions - Organic Compounds
7.2Alkenes & Alcohols
7.2.1Structure of Alkenes
7.2.2The Shortest Alkenes
7.2.3Reactions of Alkenes
7.2.4Types of Alkene Reactions
7.2.5End of Topic Test - Alkanes & Alkenes
7.2.6Alcohols
7.2.7The Smallest Alcohols
7.2.8Reactions of Alcohols
7.2.9Fermentation
7.2.10Carboxylic Acids
7.2.11The Smallest Carboxylic Acids
7.2.12Reactions of Carboxylic Acids
7.2.13Addition Polymers
7.2.14Addition Polymers Examples
7.2.15Condensation Polymers
7.2.16Amino Acids
7.2.17Naturally Occurring Polymers - Protein (Formation)
7.2.18Naturally Occurring Polymers - Protein (Roles)
7.2.19Naturally Occurring Polymers - DNA
7.2.20Naturally Occurring Polymers - Others
7.2.21End of Topic Test - Alcohols, Acids & Polymers
7.2.22Grade 9 - Organic Chemistry
7.2.23Exam-Style Questions - Alcohols
8Chemical Analysis
8.1Purity, Formulations & Chromatography
8.2Identification of Common Gases
8.3Identifying Ions
8.3.1Flame Tests
8.3.2Required Practical: Flame Tests
8.3.3Metal Hydroxides
8.3.4Metal Hydroxides 2
8.3.5Carbonates
8.3.6Halides
8.3.7Sulfates
8.3.8Methodology for Chemical Analysis
8.3.9Methodology for Chemical Analysis 2
8.3.10Flame Emission Spectroscopy
8.3.11Flame Emission Spectroscopy Analysis
8.3.12End of Topic Test - Chemical Analysis
8.3.13Grade 9 - Chemical Analysis
8.3.14Exam-Style Questions - Identification of ions
9Chemistry of the Atmosphere
9.1The Earth's Atmosphere
9.1.1Proportions of Gases in the Atmosphere
9.1.2The Earth's Early Atmosphere
9.1.3Oxygen in the Atmosphere
9.1.4Carbon Dioxide in the Atmosphere
9.1.5Greenhouse Gases
9.1.6Greenhouse Gases & Human Activities
9.1.7Greenhouse Gases & Climate
9.1.8Climate Change
9.1.9Carbon Footprints
9.1.10Carbon Footprints Barriers
9.1.11Common Atmospheric Pollutants
9.1.12Properties of Atmospheric Pollutants
9.1.13End of Topic Test - The Earth
9.1.14Grade 9 - Chemistry of the Atmosphere
9.1.15Exam-Style Questions - Earth's Atmosphere
10Using Resources
10.1Using the Earth's Resources
10.1.1Potable Water
10.1.2Potable Water Sources
10.1.3Potable Water in the UK
10.1.4Potable Water in Saudi Arabia
10.1.5Natural Resources
10.1.6Uses of Natural Resources
10.1.7Waste Water
10.1.8Sewage Treatment
10.1.9Metal Ore Extraction
10.1.10Properties of Copper
10.1.11Overexploitation of Extraction Methods
10.1.12Alternative Extraction Methods
10.2Life Cycle Assessments & Recycling
10.3Using Materials
10.4The Haber Process & NPK Fertilisers
10.4.1Plants and Nitrogen
10.4.2The Haber Process
10.4.3The Haber Process - Equation
10.4.4The Haber Process - Trade-Offs
10.4.5Importance of Fertilisers
10.4.6Formulated vs Manure Fertilisers
10.4.7NPK Fertilisers - N-containing Compound
10.4.8NPK Fertilisers - P-containing Compound
10.4.9NPK Fertilisers - K-containing Compound
10.4.10Nitrogen, Phosphorus and Potassium
10.4.11End of Topic Test - Resources
10.4.12Grade 9 - Using Resources
10.4.13Exam-Style Questions - The Haber Process
Jump to other topics
1Atomic Structure
1.1Atoms & Elements
1.1.1Elements & Compounds
1.1.2Chemical Formula
1.1.3Chemical Reactions
1.1.4Chemical Equations
1.1.5Mixtures
1.1.6Separating Mixtures
1.1.7Separating Mixtures 2
1.1.8Model of the Atom
1.1.9Sub-Atomic Particles
1.1.10Atom Size
1.1.11Atomic Number
1.1.12Atomic Number - Calculations
1.1.13Isotopes
1.1.14Isotopes HyperLearning
1.1.15Isotopes - Calculations
1.1.16Relative Atomic Mass
1.1.17Electron Structure
1.1.18Periodic Table
1.1.19The History of the Periodic Table
1.1.20Metals & Non-Metals
1.1.21Noble Gases
1.1.22Displacement Reaction
1.1.23Halogens
1.1.24Alkali Metals
1.1.25Alkali Metals - Properties
1.1.26Transition Metals
1.1.27Transition Metals - Special Properties
1.1.28End of Topic Test - Atomic Structure
1.1.29Grade 9 - Atoms & Elements
1.1.30Exam-Style Questions - Atomic Structure
1.1.31Application Questions - Atomic Structure
2Chemical Bonding
2.1Chemical Bonds
2.2States of Matter
2.3Chemical Properties
2.3.1Ionic Compounds
2.3.2Chemical Properties of Ionic Compounds
2.3.3Small Molecules
2.3.4Chemical Properties of Small Molecules
2.3.5Molecular Forces - Polymers
2.3.6Molecular Forces - Polypropene
2.3.7Giant Covalent Structures
2.3.8Metals
2.3.9Alloys
2.3.10Conductors
2.3.11Carbon Structures - Diamond
2.3.12Carbon Structures - Graphite
2.3.13Carbon Structures - Graphene
2.3.14Carbon Structures - Fullerenes
2.3.15Carbon Structures - Summary
2.3.16Clumps
2.3.17Nanoparticles
2.3.18Nanotechnology
2.3.19Nanotechnology 2
2.3.20Surface Area to Volume Ratio
2.3.21Nanotechnology Uses
2.3.22End of Topic Test - Chemical Bonding
2.3.23Grade 9 - Bonding & Structure
2.3.24Exam-Style Questions - Allotropes of Carbon
3Quantitative Chemistry
3.1Chemical Measurements
3.1.1Conservation of Mass
3.1.2Relative Formula Mass
3.1.3Calculating Relative Formula Mass
3.1.4Relative Formula Mass - Calculations
3.1.5Changing Mass
3.1.6Measuring Mass
3.1.7Equations
3.1.8Empirical Formula
3.1.9Introducing Moles
3.1.10Relative Formula Mass
3.1.11Amounts of Substance
3.1.12Moles to Balance Equations
3.1.13Limiting Reactants
3.1.14Concentration of Solutions
3.1.15Moles - Calculations
3.1.16Percentage Yield
3.1.17Calculating Yield
3.1.18Percentage Yield - Calculations
3.1.19Moles & Yield
3.1.20Moles & Yield 2
3.1.21Atom Economy
3.1.22Reaction Pathway
3.1.23Atom Economy - Calculations
3.1.24Concentrations of Solute
3.1.25Calculating the Amount of Solute
3.1.26Amount of Substance in Relation to Volumes and Gas
3.1.27Concentrations & Amounts - Calculations
3.1.28Empirical Formula - Calculations
3.1.29End of Topic Test - Quant Chemistry
3.1.30Grade 9 - Quantitative Chemistry
3.1.31Exam-Style Questions - Moles
4Chemical Changes
4.1Acids, Alkalis & Redox Reactions
4.2Reactivity of Metals
4.3Reactions of Acids
4.3.1Reactions of Metals with Acids
4.3.2Redox Reactions
4.3.3Neutralisation of Acids
4.3.4Soluble Salts
4.3.5Required Practical: Separating Mixtures
4.3.6The pH Scale
4.3.7Numerical pH Scale
4.3.8Measuring pH
4.3.9Neutralisation & Titrations
4.3.10Neutralisation & Titrations 2
4.3.11Neutralisation & Titrations 3
4.3.12Neutralisation & Titrations 4
4.3.13Strong and Weak Acids
5Energy Changes
5.1Exothermic & Endothermic Reactions
6The Rate & Extent of Chemical Change
6.1Rate of Reaction
6.2Reversible Reactions
6.2.1Reversible Reactions
6.2.2Dynamic Equilibrium
6.2.3Conditions and Equilibrium
6.2.4Equilibrium Position - Temperature
6.2.5Equilibrium Position - Pressure
6.2.6Equilibrium Position - Concentration
6.2.7End of Topic Test - Rates of Reaction
6.2.8Grade 9 - Rate & Extent of Chemical Change
6.2.9Exam-Style Questions - Reversible Reactions
7Organic Chemistry
7.1Carbon Compounds
7.1.1Crude Oil
7.1.2Properties of Hydrocarbons
7.1.3Alkanes
7.1.4Smallest Alkanes
7.1.5Fractional Distillation
7.1.6Process of Fractional Distillation
7.1.7Homologous Series
7.1.8Burning Hydrocarbons
7.1.9Heavy Fractions of Crude Oil
7.1.10Cracking
7.1.11Uses of Alkenes
7.1.12Exam-Style Questions - Organic Compounds
7.2Alkenes & Alcohols
7.2.1Structure of Alkenes
7.2.2The Shortest Alkenes
7.2.3Reactions of Alkenes
7.2.4Types of Alkene Reactions
7.2.5End of Topic Test - Alkanes & Alkenes
7.2.6Alcohols
7.2.7The Smallest Alcohols
7.2.8Reactions of Alcohols
7.2.9Fermentation
7.2.10Carboxylic Acids
7.2.11The Smallest Carboxylic Acids
7.2.12Reactions of Carboxylic Acids
7.2.13Addition Polymers
7.2.14Addition Polymers Examples
7.2.15Condensation Polymers
7.2.16Amino Acids
7.2.17Naturally Occurring Polymers - Protein (Formation)
7.2.18Naturally Occurring Polymers - Protein (Roles)
7.2.19Naturally Occurring Polymers - DNA
7.2.20Naturally Occurring Polymers - Others
7.2.21End of Topic Test - Alcohols, Acids & Polymers
7.2.22Grade 9 - Organic Chemistry
7.2.23Exam-Style Questions - Alcohols
8Chemical Analysis
8.1Purity, Formulations & Chromatography
8.2Identification of Common Gases
8.3Identifying Ions
8.3.1Flame Tests
8.3.2Required Practical: Flame Tests
8.3.3Metal Hydroxides
8.3.4Metal Hydroxides 2
8.3.5Carbonates
8.3.6Halides
8.3.7Sulfates
8.3.8Methodology for Chemical Analysis
8.3.9Methodology for Chemical Analysis 2
8.3.10Flame Emission Spectroscopy
8.3.11Flame Emission Spectroscopy Analysis
8.3.12End of Topic Test - Chemical Analysis
8.3.13Grade 9 - Chemical Analysis
8.3.14Exam-Style Questions - Identification of ions
9Chemistry of the Atmosphere
9.1The Earth's Atmosphere
9.1.1Proportions of Gases in the Atmosphere
9.1.2The Earth's Early Atmosphere
9.1.3Oxygen in the Atmosphere
9.1.4Carbon Dioxide in the Atmosphere
9.1.5Greenhouse Gases
9.1.6Greenhouse Gases & Human Activities
9.1.7Greenhouse Gases & Climate
9.1.8Climate Change
9.1.9Carbon Footprints
9.1.10Carbon Footprints Barriers
9.1.11Common Atmospheric Pollutants
9.1.12Properties of Atmospheric Pollutants
9.1.13End of Topic Test - The Earth
9.1.14Grade 9 - Chemistry of the Atmosphere
9.1.15Exam-Style Questions - Earth's Atmosphere
10Using Resources
10.1Using the Earth's Resources
10.1.1Potable Water
10.1.2Potable Water Sources
10.1.3Potable Water in the UK
10.1.4Potable Water in Saudi Arabia
10.1.5Natural Resources
10.1.6Uses of Natural Resources
10.1.7Waste Water
10.1.8Sewage Treatment
10.1.9Metal Ore Extraction
10.1.10Properties of Copper
10.1.11Overexploitation of Extraction Methods
10.1.12Alternative Extraction Methods
10.2Life Cycle Assessments & Recycling
10.3Using Materials
10.4The Haber Process & NPK Fertilisers
10.4.1Plants and Nitrogen
10.4.2The Haber Process
10.4.3The Haber Process - Equation
10.4.4The Haber Process - Trade-Offs
10.4.5Importance of Fertilisers
10.4.6Formulated vs Manure Fertilisers
10.4.7NPK Fertilisers - N-containing Compound
10.4.8NPK Fertilisers - P-containing Compound
10.4.9NPK Fertilisers - K-containing Compound
10.4.10Nitrogen, Phosphorus and Potassium
10.4.11End of Topic Test - Resources
10.4.12Grade 9 - Using Resources
10.4.13Exam-Style Questions - The Haber Process
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