Grade 10
  1. Matter and its properties  1.1. States of matter  1.2. Physical and chemical properties of matter  1.3. Classification of substances (elements, compounds, mixtures)  1.4. Changes in Matter (Physical and Chemical Changes)  1.5. Law of conservation of mass and law of definite proportions
  2. Atomic Structure  2.1. Historical development of the atomic model  2.2. Subatomic particles (protons, neutrons, electrons)  2.3. Atomic number, mass number and isotopes  2.4. Electronic Configuration and Energy Levels  2.5. Valency, ion formation and oxidation state
  3. Periodic table  3.1. History and Development of the Periodic Table  3.2. Modern Periodic Law and Periodic Trends  3.3. Groups and Periods in the Periodic Table  3.4. Trends in the Periodic Table  3.5. Metals, non-metals, metalloids and their properties  3.6. Noble gases and their chemical inertness
  4. Chemical bond  4.1. Formation of Chemical Bonds (Octet Rule)  4.2. Ionic Bonding and Properties of Ionic Compounds  4.3. Covalent Bond and Properties of Covalent Compounds  4.4. Metallic bond and its properties  4.5. Molecular geometry and VSEPR theory  4.6. Polarity and dipole moment of molecules  4.7. Intermolecular forces
  5. Chemical Reactions and Equations  5.1. Types of Chemical Reactions  5.2. Writing and balancing chemical equations  5.3. Law of conservation of mass in chemical reactions  5.4. Factors Affecting Chemical Reactions  5.5. Catalysts and their role in chemical reactions  5.6. Exothermic and Endothermic Reactions
  6. Stoichiometry and Chemical Calculations  6.1. Mole concept and Avogadro number  6.2. Molar Mass and Gram-Mole Conversions  6.3. Empirical and molecular formula  6.4. Stoichiometric calculations and chemical yield  6.5. Limiting and Excess Reactants
  7. Acids, Bases and Salts  7.1. Properties and Definitions of Acids and Bases (Arrhenius, Bronsted-Lowry, Lewis)  7.2. pH Scale, pOH, and Indicators  7.3. Neutralization reactions and salt formation  7.4. Strength of Acids and Bases (Strong vs. Weak Acids and Bases)  7.5. Common Acids and Bases in Daily Life  7.6. Salts, their solubility and applications
  8. Metals and Nonmetals  8.1. Physical and chemical properties of metals  8.2. Physical and Chemical Properties of Non-Metals  8.3. Reactivity Series of Metals and Displacement Reactions  8.4. Extraction of metals from ores  8.5. Corrosion, its causes and prevention  8.6. Alloys, their composition and uses
  9. Carbon and its compounds  9.1. Allotropes of Carbon  9.2. Hydrocarbons and their classification (alkanes, alkenes, alkynes)  9.3. Functional groups in organic compounds  9.4. Nomenclature of organic compounds (IUPAC system)  9.5. Isomerism in organic chemistry (structural and geometrical)  9.6. Important organic reactions (combustion, addition, substitution, polymerization)  9.7. Applications of organic compounds in industry and daily life
  10. Environmental Chemistry  10.1. Air Pollution (Sources, Effects and Control)  10.2. Water Pollution (Causes, Effects and Remedies)  10.3. Greenhouse effect and global warming  10.4. Ozone layer depletion and its effects  10.5. Green Chemistry and Its Applications  10.6. sustainable chemistry practice
  11. Thermochemistry  11.1. Heat and Energy Changes in Chemical Reactions  11.2. Exothermic and Endothermic Reactions  11.3. Enthalpy, enthalpy change, and heat of reaction  11.4. Specific heat capacity and calorimetry  11.5. Energy Changes in Combustion Reactions
  12. Electrochemistry  12.1. Electrolytes and non-electrolytes  12.2. Electrolysis and its applications (electroplating, extraction of metals)  12.3. Redox reactions (oxidation and reduction)  12.4. Galvanic cell and electrochemical series  12.5. Corrosion and electrochemical prevention methods
  13. Chemical kinetics and equilibrium  13.1. Rate of chemical reactions and its measurement  13.2. Factors affecting the reaction rate (catalyst, temperature, concentration)  13.3. Reversible and irreversible reactions  13.4. Dynamic equilibrium and equilibrium constant  13.5. Le Chatelier's principle and its applications
  14. Gases and Gas Laws  14.1. Properties of gases and kinetic molecular theory  14.2. Boyle's Law (Pressure-Volume Relation)  14.3. Charles's Law  14.4. Gay-Lussac's Law  14.5. Combined Gas Law and Ideal Gas Law  14.6. Real Gases vs Ideal Gases
  15. Nuclear Chemistry  15.1. Introduction to Radioactivity and Nuclear Reactions  15.2. Types of radioactive decay (alpha, beta, gamma)  15.3. Half-life and applications of radioactive isotopes  15.4. Nuclear fission and fusion reactions  15.5. Nuclear power generation and its environmental impact

Grade 10 → Matter and its properties ↓


Classification of substances (elements, compounds, mixtures)


The study of matter is an important part of chemistry. Matter is something that has mass and occupies space. All the substances you see around you are made of matter, and they can be divided into different categories. This classification helps to study and understand matter better. The primary groups are elements, compounds, and mixtures.

Elements

Elements are pure substances that cannot be broken down into simpler substances by chemical means. They are the building blocks of all matter. Each element is made up of one type of atom. The periodic table of the elements lists all known elements. Examples of elements include:

  • Hydrogen (H)
  • Oxygen (O)
  • Carbon (C)
  • Gold (Au)

Each element has a different atomic structure. For example, a hydrogen atom has one proton and one electron, while a carbon atom has six protons and six electrons.

Visual example of an element

H

The picture above is a simplified representation of a hydrogen atom. It has one proton and one electron.

Compounds

Compounds are substances that are formed when two or more elements are chemically joined together. When a compound is formed, the elements lose their individual properties and take on new properties. For example, water (H2O) is made of hydrogen and oxygen, and the two elements have different properties than water alone.

Some examples of compounds include:

  • Water (H2O)
  • Carbon dioxide (CO2)
  • Sodium Chloride (NaCl)
  • Methane (CH4)

Example of a compound - water

HH  / O

This is a simplified diagram showing the molecular structure of water. Each water molecule is made up of two hydrogen atoms and one oxygen atom.

Mixture

A mixture is a combination of two or more substances where each substance retains its individual chemical properties. Unlike compounds, the components of a mixture can be separated by physical means. Mixtures can be classified as homogeneous or heterogeneous.

Homogeneous mixture

Homogeneous mixtures are uniform in structure, meaning you can't see the individual parts. These are also known as solutions. The air we breathe is a good example of this, as it is made up of oxygen, nitrogen, and other gases that are thoroughly mixed together.

Another example is sugar water, where the sugar is completely dissolved in the water.

Visual example of homogeneous mixture

sugar water

This represents a glass of sugar water, with the sugar mixed evenly throughout the water.

Heterogeneous mixtures

Heterogeneous mixtures have distinct, visible parts. A classic example of this is a salad, where you can see and identify the individual components, such as lettuce, tomatoes, and cucumbers. Another example is a rock that has different minerals inside it.

Visual example of a heterogeneous mixture

Salad

It is a salad with its various components clearly visible.

Separating mixtures

Mixtures can be separated using physical processes based on differences in the properties of their components. Common separation methods include:

Filtration

This method is used to separate solids from liquids. For example, separating coffee grounds from liquid coffee using a coffee filter.

Distillation

Distillation involves heating a liquid to form a vapor and then cooling the vapor to form a liquid. It is used to separate components based on boiling point, such as separating alcohol from water.

Chromatography

This method is used to separate and analyse complex mixtures. It is based on the movement of different substances at different speeds in a medium.

Physical and chemical properties

Understanding matter also includes the study of its physical and chemical properties.

Physical properties

These are characteristics of a substance that can be observed without changing the chemical identity of the substance. Physical properties include:

  • Colour
  • Dirt
  • Melting point
  • Boiling point
  • Density

Chemical properties

Chemical properties describe the ability of a substance to undergo a chemical change or reaction. These properties become apparent during a chemical reaction. Examples include:

  • Reactivity with acids
  • Combustibility
  • pH
  • Corrosion resistance

Chemical reactions

Chemical reactions involve the transformation of reactants into products and it is essential to understand how matter reacts and changes. A simple example of this could be the reaction between vinegar and baking soda:

CH3COOH + NaHCO3 → CO2 + H2O + NaC2H3O2

Visualization of chemical reactions

vinegar baking soda feedback

This diagram shows a simple interaction between vinegar and baking soda, resulting in a reaction that produces gases, such as carbon dioxide, which is called fizzing.

Key concepts to remember

  • Elements are pure substances containing one type of atom.
  • Compounds are substances formed by the chemical combination of two or more elements.
  • A mixture is a combination of substances in which each substance retains its own properties.
  • Mixtures may be homogeneous or heterogeneous.
  • Understanding the chemical and physical properties helps predict behavior during reactions.
  • Chemical reactions involve the transformation of reactants into products with new properties.

Conclusion

Classifying substances into elements, compounds, and mixtures helps chemists understand and predict how substances will interact. Whether it's identifying the basic elements on the periodic table, understanding new properties of compounds, or determining the best ways to separate mixtures, each concept plays an important role in chemistry. With this knowledge, you are better equipped to explore the world of matter and its properties.


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Classification of substances (elements, compounds, mixtures)

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