Fundamentals of Chemistry
In chemistry 9 chapter 1 notes fundamental of chemistry, we will explore the fundamentals of chemistry. Students will identify different branches of chemistry and understand their distinctions. They will also learn in chemistry 9 chapter 1 notes fundamental of chemistry to differentiate between matter and specific substances. Key concepts like ions, molecular ions, and atomic mass will be defined clearly.
Branches of Chemistry
Chemistry has several branches. Each branch focuses on different aspects of matter and its behavior.
Physical Chemistry
Physical chemistry studies how matter’s makeup affects its properties. It examines atomic structure and the behavior of solids, liquids, and gases. This branch also explores temperature and radiation’s impact on matter.
Organic Chemistry
Organic chemistry focuses on carbon-based compounds. These compounds include hydrocarbons and their derivatives. Organic chemists study both natural and synthetic compounds, which are essential in various industries.
Inorganic Chemistry
Inorganic chemistry deals with all elements and compounds except carbon-hydrogen compounds. It finds applications in industries like glass, cement, and metallurgy.
Biochemistry
Biochemistry examines the chemical reactions in living organisms. It focuses on substances found in biological systems.
Basic Definitions
Matter is anything with mass that occupies space. We study matter in three states: solid, liquid, and gas. A pure piece of matter is a substance with a fixed composition. In contrast, a mixture contains two or more substances and can be homogeneous or heterogeneous.
Properties of Matter
Every substance has physical and chemical properties. Physical properties include color, hardness, and boiling point. For example, ice melts into water when heated. However, the chemical composition of water remains unchanged.
Chemical properties relate to how substances react. When water breaks down into hydrogen and oxygen, it undergoes a chemical change. All materials classify as either substances or mixtures.
Elements
Initially, only nine elements were known. Today, there are 118 elements, with 92 occurring naturally. An element consists of the same type of atom and cannot break down further.
Elements can be solids, liquids, or gases. Most elements are solids, while a few, like mercury, are liquids. Gaseous elements include nitrogen and oxygen.
Element Categories
Elements fall into three categories: metals, non-metals, and metalloids. About 80% are metals. Each element has a symbol derived from its name. For instance, H represents hydrogen.
A key property of an element is its valency. Valency indicates how an element combines with others. For example, chlorine has a valency of 1, while oxygen has 2.
Compounds
A compound forms when two or more elements combine chemically. Compounds cannot break down into their original elements by physical means. For example, carbon dioxide and water are compounds formed from specific ratios of elements.
Types of Compounds
Compounds can be ionic or covalent. Ionic compounds form strong attractions in a crystal structure. They have high melting points and are represented by formula units like NaCl.
Covalent compounds exist as molecules. Their formulas show how atoms combine, such as H₂O for water.
Mixtures
A mixture consists of two or more substances physically combined. Each substance retains its identity. Mixtures can separate using physical methods like filtration or evaporation.