Grade 7
  1. Introduction to Chemistry  1.1. What is Chemistry?  1.2. Importance of chemistry in daily life  1.3. Branches of chemistry  1.4. Scientific Method in Chemistry  1.5. Laboratory Safety Rules and Precautions  1.6. Common Laboratory Equipment and Their Uses  1.7. Units of measurement in chemistry
  2. Matter and its properties  2.1. Definition of Matter  2.2. Classification of matter  2.3. Properties of matter  2.3.1. Physical properties  2.3.2. Chemical properties  2.4. States of matter  2.4.1. Solid state  2.4.2. Fluid state  2.4.3. Gaseous state  2.4.4. Plasma and Bose–Einstein condensates  2.5. Changes in the states of matter  2.5.1. Melting and freezing  2.5.2. Evaporation and Condensation  2.5.3. Sublimation and deposition  2.6. Density and its applications  2.7. Diffusion and its importance
  3. Elements, Compounds, and Mixtures  3.1. Definition of the element  3.2. Classification of elements  3.3. Metals, Nonmetals and Metalloids  3.4. Noble gases and their properties  3.5. Introduction to the Periodic Table  3.6. Definition of Compound  3.7. Properties of Compounds  3.8. Introduction to Chemical Formulas  3.9. Definition of Mixture  3.10. Types of mixtures  3.10.1. Homogeneous mixture  3.10.2. Heterogeneous mixtures  3.11. Difference Between Compounds and Mixtures  3.12. Solutions, Colloids and Suspensions
  4. Separation of mixtures  4.1. Need for separation of mixtures  4.2. Separation methods  4.2.1. Filtration  4.2.2. Sedimentation and decantation  4.2.3. Evaporation  4.2.4. Crystallization  4.2.5. Distillation  4.2.6. Chromatography  4.2.7. Magnetic Separation  4.2.8. Centrifugation
  5. Atomic Structure  5.1. Introduction to Atoms  5.2. Structure of the atom  5.2.1. Nucleus and electron cloud  5.3. Subatomic particles  5.3.1. Proton  5.3.2. Neutron  5.3.3. Electrons  5.4. Atomic number and mass number  5.5. Isotopes and their uses  5.6. Ions and ion formation
  6. Periodic table  6.1. Introduction to the Periodic Table  6.2. Groups and periods  6.3. Trends in the Periodic Table  6.3.1. Atomic Size  6.3.2. Metallic and non-metallic character  6.3.3. Electronegativity  6.3.4. Reactivity of the elements  6.4. Alkali metals and their properties
  7. Chemical bond  7.1. Why do atoms form bonds?  7.2. Types of chemical bonds  7.2.1. Ionic bond  7.2.2. Covalent bond  7.2.3. Metal Bond  7.3. Properties of Ionic and Covalent Compounds  7.4. Intermolecular forces
  8. Chemical reactions  8.1. Introduction to Chemical Reactions  8.2. Signs of a chemical reaction  8.3. Types of Chemical Reactions  8.3.1. Combination Reactions  8.3.2. Decomposition reactions  8.3.3. Displacement reactions  8.3.4. Double displacement reactions  8.3.5. Combustion reactions  8.4. Law of conservation of mass  8.5. Balancing simple chemical equations
  9. Acids, Bases and Salts  9.1. Definition of Acid and Base  9.2. Properties of Acids  9.3. Properties of bases  9.4. pH Scale and Indicators  9.5. Neutralization reactions  9.6. Common Acids and Bases in Everyday Life  9.7. Preparation and use of salts  9.8. Strong and weak acids and bases
  10. Solutions and Solubility  10.1. Definition of Solution  10.2. Components of the solution  10.2.1. Solvent  10.2.2. solute  10.3. Factors Affecting Solubility  10.4. Concentration of solutions  10.5. Saturated and unsaturated solutions  10.6. Colloids and suspensions  10.7. Solubility curve and its interpretation
  11. Air and atmosphere  11.1. Composition of air  11.2. Properties of gases in the air  11.3. Importance of Oxygen and Carbon Dioxide  11.4. Air pollution and its effects  11.5. Greenhouse effect and global warming  11.6. Ways to reduce air pollution  11.7. Ozone layer and its importance
  12. Water and its importance  12.1. Properties of Water  12.2. Water as the universal solvent  12.3. Importance of water for life  12.4. Water pollution and its effects  12.5. Water Purification  12.5.1. Filtration  12.5.2. boil  12.5.3. Chlorination in water purification  12.5.4. reverse osmosis  12.6. Hard and soft water  12.7. Water cycle and its importance
  13. Fuel and energy  13.1. Types of fuel  13.1.1. Fossil fuels  13.1.2. Renewable energy sources  13.2. Combustion and energy release  13.3. Global warming and its effects  13.4. Alternative sources of energy  13.5. Ways to conserve energy
  14. Metals and Nonmetals  14.1. Physical and chemical properties of metals  14.2. Physical and Chemical Properties of Non-Metals  14.3. Difference Between Metals and Nonmetals  14.4. Uses of metals and nonmetals  14.5. Corrosion of metals and its prevention  14.6. Alloys and their importance
  15. Plastics and polymers  15.1. Natural and synthetic polymers  15.2. Properties of plastics  15.3. Biodegradable and Non-Biodegradable Plastics  15.4. Environmental impact of plastic  15.5. Recycling and waste management in plastics and polymers  15.6. Daily Uses of Polymers
  16. Introduction to Organic Chemistry  16.1. Basic definitions of organic chemistry  16.2. Carbon Compounds in Daily Life  16.3. Hydrocarbons  16.4. Simple functional groups (alcohols and carboxylic acids)  16.5. Importance of organic compounds in industry

Grade 7 → Solutions and Solubility ↓


Components of the solution


In Class 7 Chemistry, understanding solutions and solubility is fundamental. Let's learn about the basic components of a solution and how solubility works. A solution is a homogeneous mixture, which means that the components are evenly distributed and have the same composition. Studying solutions helps us understand how different substances can mix and interact with each other.

The main components of the solution

A solution is made up of two primary components:

  1. Solvent
  2. Solute

Solvent

The solvent is the component of a solution that is present in the largest amount. It is the substance that dissolves the solute. In most cases, the solvent is usually a liquid, but it can also be a solid or a gas. Water is often referred to as the "universal solvent" because it can dissolve many substances. Let's take a closer look at how water acts as a solvent:

H2O

The chemical formula for water is H 2 O, which indicates that it is composed of two hydrogen (H) atoms and one oxygen (O) atom. The molecular structure of water gives it the ability to dissolve a wide variety of substances.

Solute

The solute is the component that dissolves in the solvent. The solute is often present in smaller quantities than the solvent. The solute can be a solid, liquid, or gas. For example, when you dissolve salt in water, the salt is the solute.

Understanding solubility

Solubility is a measure of how much of a solute can dissolve in a solvent at a given temperature and pressure. It is important to understand that not all solutes dissolve in all solvents. The solubility of a substance depends on many factors, including the nature of the solute, the nature of the solvent, temperature, and pressure.

Factors affecting solubility

  1. Nature of solute and solvent

    Like dissolves like. This means that polar solutes dissolve well in polar solvents, while nonpolar solutes dissolve better in nonpolar solvents. For example, sugar dissolves well in water (both are polar), but oil does not dissolve in water (oil is nonpolar).

  2. Temperature

    Generally, the solubility of solids in liquids increases with an increase in temperature. For example, more sugar can dissolve in hot water than in cold water. However, the solubility of gases in liquids decreases with an increase in temperature. This is why cold soda retains more fizz than a hot one.

  3. Pressure

    Pressure mainly affects the solubility of gases. An increase in pressure increases the solubility of gases in liquids. This is noticeable in carbonated drinks, where carbon dioxide dissolves under high pressure.

Visual example: dissolving sugar in water

Let's visualize how sugar dissolves in water. Consider the diagram below in which sugar (the solute) is mixed with water (the solvent) to form a sugar solution:

solute Solvent

As the sugar dissolves, its molecules spread out evenly in the water, creating a homogeneous mixture.

Types of solutions

Solutions can be classified based on various criteria. The common types of solutions are as follows:

  1. Solid solution

    These include alloys such as brass (a mixture of copper and zinc) and steel (a mixture of iron and carbon).

    Example: Cu + Zn → Brass
  2. Liquid solution

    Examples include sugar dissolved in water or alcohol mixed with water.

  3. Gaseous solution

    An example of this is air, which is a mixture of various gases such as nitrogen (N2), oxygen (O2) and other trace gases.

Saturation of solutions

The concept of saturation is related to the amount of solute that can dissolve in the solvent. Solutions can be classified as:

  1. Unsaturated solution

    A solution that can dissolve more solute at a given temperature is called an unsaturated solution. For example, adding a teaspoon of sugar to a glass of water usually results in an unsaturated solution because more sugar can dissolve.

  2. Saturated solution

    In a saturated solution, the maximum amount of solute is dissolved at a given temperature. On adding more solute, undissolved particles are formed at the bottom.

    Example: If more sugar is added to a saturated sugar solution it remains undissolved.
  3. Supersaturated solution

    A supersaturated solution contains more solute than a saturated solution at the same temperature. It is usually obtained by heating a saturated solution, dissolving the excess solute, and then cooling it slowly. It is unstable and can easily crystallize.

Practical applications of solutions

The solutions are vital in many everyday applications and industrial processes.

  • Pharmaceuticals: Many medications are formulated as solutions so they can be more easily absorbed by the body.
  • Agriculture: Fertilizers are used in solutions to deliver essential nutrients to plants.
  • Chemical reactions: Many chemical reactions occur in solutions because they allow the reactants to interact efficiently.

Conclusion

Understanding the components of a solution and solubility is vital in chemistry. The interaction between a solute and a solvent and the factors that affect solubility are fundamental concepts with wide-reaching implications. Our exploration of solutions helps us understand the nature of countless everyday phenomena and industrial processes, giving us a clearer understanding of the world around us.


Grade 7 → 10.2


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Definition of Solution
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Components of the solution

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