Grade 8
  1. Introduction to Chemistry  1.1. Nature and scope of chemistry  1.2. Importance of chemistry in daily life  1.3. Chemistry and its relation with other sciences  1.4. The role of chemistry in industry, medicine and the environment  1.5. Scientific investigation and experimental methods in chemistry
  2. Matter and its properties  2.1. Definition and classification of matter  2.2. Physical and chemical properties of matter  2.3. Law of conservation of matter  2.4. Extensive and Intensive Properties of Matter  2.5. Kinetic molecular theory of matter  2.6. States of matter: solids, liquids, gases, plasmas, and Bose-Einstein condensates  2.7. Changes in state and energy are involved  2.8. Diffusion and Brownian motion
  3. Elements, Compounds, and Mixtures  3.1. Definition and differences between elements, compounds, and mixtures  3.2. Atomic Structure and Atomic Number  3.3. Chemical symbols and formulas  3.4. Trends in the Periodic Table (Groups and Periods)  3.5. Classification of Elements: Metals, Nonmetals and Metalloids  3.6. Rare Earth Elements and Transition Metals  3.7. Types of mixtures: homogeneous and heterogeneous  3.8. Separation of Mixtures Using Physical and Chemical Methods
  4. Separation Techniques  4.1. Filtration, Sedimentation and Decantation  4.2. Evaporation and crystallization  4.3. Distillation and Fractional Distillation  4.4. Chromatography and its applications  4.5. Sublimation in the purification of compounds  4.6. The role of centrifugation in biochemical processes
  5. Atomic Structure  5.1. Dalton's atomic theory  5.2. Structure of the atom: protons, neutrons and electrons  5.3. Bohr's atomic model  5.4. Introduction to Quantum Mechanical Model  5.5. Electron Configuration and Energy Levels  5.6. Excitation and emission spectra  5.7. Isotopes and their applications
  6. Periodic Table and Chemical Trends  6.1. History and Development of the Periodic Table  6.2. Modern periodic law  6.3. Periodicity and trends in atomic and ionic sizes  6.4. Ionization Energy, Electron Affinity and Electronegativity  6.5. Introduction to Lanthanides and Actinides  6.6. Application of periodic trends in chemistry
  7. Chemical Bonding and Molecular Structure  7.1. Types of chemical bonds: ionic, covalent and metallic bonds  7.3. Polar and Nonpolar Molecules  7.4. Hydrogen bonding and its applications  7.5. Intermolecular forces: dipole-dipole, London dispersion force
  8. Chemical Reactions and Stoichiometry  8.1. Chemical Equations and Balance  8.2. Types of Chemical Reactions: Combination, Decomposition, Displacement and Redox  8.3. Introduction to stoichiometry and the mole concept  8.4. Limiting reactant in chemical equations  8.5. Reaction rate, catalyst, and factors affecting reaction rate
  9. Acids, Bases and Salts  9.1. Definition and Properties of Acids and Bases  9.2. Strong vs. Weak Acids and Bases  9.3. pH Scale and pH Calculation  9.4. Neutralization reactions  9.5. Buffer solutions and their importance  9.6. Applications of Acids, Bases and Salts in Daily Life
  10. Solutions and Solubility  10.1. Definition of Solution, Solute, and Solvent  10.2. Factors Affecting Solubility  10.3. Concentration units: molarity and molality  10.4. Saturated, unsaturated and supersaturated solutions  10.5. Concept of osmosis and reverse osmosis  10.6. Concentrative properties of solutions
  11. Gases and Gas Laws  11.1. Properties of gases  11.2. Introduction to Ideal and Real Gases  11.3. Boyle's Law, Charles' Law and Avogadro's Law  11.4. Ideal Gas Equation and Its Applications  11.5. Application of Gas Laws in Real Life
  12. Thermochemistry and energy transformation  12.1. Energy in Chemical Reactions  12.2. Exothermic vs. Endothermic Reactions  12.3. Heat and Enthalpy Changes  12.4. Calorimetry and heat transfer in reactions
  13. Metals and Nonmetals  13.1. Physical and Chemical Properties of Metals and Nonmetals  13.2. Reactivity Series of Metals  13.3. Corrosion and its prevention  13.4. Extraction of metals from ores  13.5. Uses of metals and non-metals in daily life
  14. Introduction to Organic Chemistry  14.1. Characteristics of carbon and organic compounds  14.2. Functional groups and their importance  14.3. Simple Hydrocarbons: Alkenes, Alkenes and Alkynes  14.4. Isomerism in organic compounds  14.5. Introduction to polymers and their uses
  15. Environmental Chemistry and Sustainability  15.1. Green Chemistry Principles  15.2. Effects of Chemical Pollution on Ecosystems  15.3. Acid rain and its effects  15.4. Ozone layer depletion and global warming  15.5. Waste Management and Recycling in Chemistry

Grade 8 → Matter and its properties ↓


Physical and chemical properties of matter


To understand the world we live in, we need to study the various materials and substances that make up everything around us. This is where the study of matter in chemistry becomes essential. Matter is something that has mass and occupies space. It exists in various forms and exhibits a variety of properties. These properties help us identify, classify, and use matter in an appropriate manner. In this comprehensive exploration, we will learn about the physical and chemical properties of matter.

What is the matter?

First, matter is anything that occupies space and has mass. Everything you see, touch, taste, and even some things you can't see, like air, are examples of matter. Matter exists in four primary states: solid, liquid, gas, and plasma.

Solid liquid

To understand different types of matter, scientists rely on their properties, which fall into two broad categories: physical properties and chemical properties.

Physical properties of matter

Physical properties are characteristics that can be observed or measured without changing the identity of the substance. They are intrinsic to the substance and vary from one substance to another. Physical properties are often used to describe a substance.

Examples of physical properties:

  • Colour: It is the appearance of an object based on the way it reflects or emits light.
  • Density: It is the mass of a substance per unit volume. It is calculated using the formula: Density = Mass / Volume.
  • Boiling point and melting point: These are the temperatures at which a substance changes its state. For example, water boils at 100°C and melts at 0°C.
  • Solubility: It is the ability of a substance to dissolve in another substance.
  • Conductivity: The ability to conduct electricity or heat.

Understanding physical properties through examples

Let us consider ice. Ice is water in the solid state. It is colourless in small quantities and translucent in large quantities. Ice melts at 0°C, a property that helps to identify and distinguish it from other substances.

Ice (solid) Water (liquid)

When you hold a piece of ice, you can feel its cold and hard nature, which gives information about its physical properties. Components such as shape, colour, texture and phase changes help us understand what the matter is, without changing its basic form.

Chemical properties of matter

Chemical properties are characteristics of a substance that become apparent during a chemical reaction; in other words, they are properties that become apparent when a change occurs in a substance that results in the formation of a new substance.

Examples of chemical properties:

  • Reactivity: The ability of a substance to react chemically with other substances. For example, iron reacts with oxygen to form rust due to its reactivity.
  • Flammability: The ability of a substance to burn or ignite.
  • Acidity or basicity: It is the pH level of a substance that determines whether it is an acid or a base.
  • Oxidation states: Indicates the degree of oxidation (loss of electrons) of an atom in a chemical compound.

Understanding chemical properties through examples

When you leave an iron nail exposed to the atmosphere, it begins to rust over time. This happens because of a chemical reaction between iron and oxygen, a property of iron called its reactivity with oxygen.

Iron (before responding) iron oxide (after giving feedback)

Such properties help chemists predict how substances will behave with each other, whether they will form new compounds, or whether they will explode under certain conditions.

Comparison between physical and chemical properties

When discussing physical and chemical properties, it is necessary to differentiate between the two as they provide different information about the nature of substances.

Physical properties Chemical properties
This can be observed without changing the matter. This can only be observed by changing the chemical identity of the substance.
Density, color, boiling/melting point Reactivity, flammability, acidity
The examples do not involve chemical reactions. Examples often involve chemical reactions.

Practical implications of understanding the properties of matter

Identification and understanding of the properties of matter have many practical implications in daily life as well as in scientific industries.

When you cook food, you rely on the physical properties of ingredients, such as boiling point and solubility, to ensure they are cooked properly. Similarly, industries use chemical properties to innovate and create products such as pharmaceuticals, plastics and alloys through predicting chemical reactions and the behavior of matter.

Conclusion

Whether you are mixing ingredients for a cake, painting a wall, developing a new medicine or studying the environment, it is important to identify and understand the physical and chemical properties of matter. By understanding how substances behave and interact, we not only understand existing materials but also invent and derive new materials and solutions for various applications.

This insight opens the doors to infinite possibilities, and fuels the advancement of science and technology, which have a profound impact on our daily lives and the world at large.


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Physical and chemical properties of matter

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