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 → Introduction to Chemistry ↓


What is Chemistry?


Chemistry is a branch of science that studies matter: what it's made of, what properties it has and how it changes. In simple terms, chemistry is about looking at things around you and understanding what that thing is, how it behaves and why it behaves that way.

Basics of chemistry

Everything you can touch, taste, smell and see is made of chemicals. Chemistry is often called the "central science" because it connects other sciences such as biology, physics, geology and environmental science. Let's explore some basic concepts of chemistry.

Atoms and molecules

The foundation of chemistry is atoms. Atoms are the tiny particles that make up everything around us. If you could shrink down to the size of an atom, you would see that everything is made up of these tiny building blocks. There are over 100 different types of atoms and they are known as elements.

In the view above, you can see a simple model of an atom. In the center is a red circle, representing the nucleus, which is made up of protons and neutrons. The blue circles are the electrons orbiting the nucleus.

Elements

An element is a substance made up entirely of one type of atom. For example, the element gold is made up of only gold atoms. Other examples of elements are carbon, oxygen, and hydrogen. Each element has unique properties. Two elements cannot be broken down into simpler substances. They are represented in the periodic table of elements, which organizes all known elements based on their properties.

Compounds and mixtures

A compound is a substance made of two or more different elements that are chemically bonded together. For example, water is a compound made of hydrogen and oxygen, with the chemical formula H2O

2H2 + O2 → 2H2O

A mixture is a combination of two or more substances that are not chemically bonded. An example of a mixture is a salad. You can easily separate tomatoes from the salad because they are not bonded together.

Mixture Mixture

States of matter

Matter can exist in many different forms, called states. The most common states of matter on Earth are solid, liquid, and gas. Let's look at each of these states and see how particles behave in each state.

Solid

The particles in a solid are tightly bound to one another. They do not move freely, but vibrate in place, giving the solid a definite shape and volume. Rock, ice, and a wooden table are all examples of solid matter.

Liquid

The particles in a liquid are still close together but can flow around each other. This allows liquids to take the shape of their container while maintaining a constant volume. Examples include water, milk, and oil.

Gas

The particles in a gas are far apart and move around freely, causing gases to expand and fill their containers. Gases have no definite shape or volume. Air is a mixture of gases such as oxygen and nitrogen.

Chemical reactions

A chemical reaction occurs when substances change into new substances. It involves the breaking and making of chemical bonds. Chemical reactions are happening all around us all the time. For example, when you make a cake, chemical changes occur as the ingredients mix together and cook.

A simple and common chemical reaction is the reaction between vinegar and baking soda. Here is its chemical equation:

NaHCO3 + CH3COOH → CO2 + H2O + Na+ + CH3COO-

In this reaction, baking soda (sodium bicarbonate, NaHCO3 ) reacts with vinegar (acetic acid, CH3COOH ) to form carbon dioxide gas ( CO2 ), water ( H2O ), and sodium acetate ( NaCH3COO ).

Applications of chemistry

Chemistry is not only available in laboratories. It is used in various fields and everyday activities. Let's take a look at some applications of chemistry.

Cooking

Cooking is basically using chemistry. When you heat food, chemical reactions occur. Proteins denature, sugars caramelize, and flavors develop, all thanks to chemistry.

Medicine

Chemistry is very important in the manufacture of medicines. Understanding the chemical properties of drugs helps scientists create effective medicines to treat diseases and improve quality of life.

Environmental chemistry

This field of chemistry helps us understand the effects of pollutants, develop sustainable materials, and improve recycling processes. Environmental chemists work to solve problems related to air and water quality.

Materials science

Chemistry is used to design and synthesize new materials, from plastics to metals and nanomaterials. It helps adjust properties such as strength, flexibility, and conductivity of materials used in various technologies.

Role of chemistry in our life

Chemistry plays a fundamental role in our daily lives. The moment we wake up, chemistry starts working, influencing our actions and experiences. It is present in our toothpaste, soap, food, the air we breathe, and even inside our bodies.

For example, the digestive process is a complex series of chemical reactions in which enzymes break down the food we eat into smaller molecules that our bodies can use for energy and repair. Even our emotions, such as happiness, are influenced by chemical reactions in our brain involving neurotransmitters such as dopamine and serotonin.

Understanding chemistry not only helps us understand the world around us, but it also enables us to make informed decisions in our daily lives, whether it's choosing safe household products, understanding nutritional information, or contributing to discussions about environmental sustainability.


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What is Chemistry?

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