Some Basic Concepts in Chemistry

Chemistry is an important branch of science. Chemistry plays a significant role in our life. There are some basic concepts in chemistry that a person needs to understand. One of the main concepts in chemistry is matter, which is present in our environment in different forms. In this article, we will discuss some basic concepts in chemistry and a few related topics in detail.

Let’s start with the importance of chemistry.

Importance of Chemistry

Chemistry plays a significant role in science and is interlinked with the other branches of science. It can be applied in various areas like computer operation, manufacturing and protection fields of industries like salts, dye, soaps, etc., weather patterns, functioning of the brain, and production of medicine.

Chemistry not only helps in the development and growth of a nation but also helps in finding alternative solutions for environmental problems, such as greenhouse gases like carbon dioxide.

Nature of Matter

• Matter, anything that occupies space and has mass, is available in three different forms: Solid, Liquid, and Gases.
  • Solid has a definite volume and shape.
  • Liquid has a definite volume but no definite shape.
  • Gases don’t have a definite volume and shape.
• On heating, solids change into liquids, and liquids convert into gas.
• There are two types of matter: Mixtures and Pure Substances.
  • Pure substances have particles that are the same in chemical nature. 
  • The mixture contains particles of two and more substances. 

Properties of Matter and their Measurement

• There are two types of properties of matter. They are as follows: 

1. Physical properties: can be observed and measured without altering the composition of the substance.
2. Chemical Properties: can be observed after the chemical change.

• There were two measurement systems that were being used before the SI system.
• The SI system has seven basic units; for example, the kilogram is a SI unit for the mass. 
• Mass can be defined as the amount of matter present in a substance, while weight is the force due to gravity on an object. 
• Mass is constant while weight varies due to a change of gravity.
• Volume can be defined as the amount of space occupied by a substance. Unit of a volume is (length)3.
• The density of a substance= massVolume , SI unit of density = kgm3
• Temperature can be measured in three units: kelvin, Fahrenheit, and Celcius, where the SI unit of temperature is Kelvin.

Scientific Notation

In chemistry, atoms and molecules have extremely low masses with so many zeros. Exponential notation of any number is represented in the form N 10n, where n is an exponent having +ve and -ve values. For example, 506.213 can be written as 5.06213 102 .

Calculations of 

Multiplications: 5.8 102 * 4.2 103 = 24.36102+3 = 24.36105

Division:  5.8 106 1.9 102 = 5.8 106 1.9 102 = 5.81.9 106-2 = 3 104

Addition:  5.8 102 + 4.2 103 = (5.8+42) 102 = 47.8 102

Subtraction: 5.8 103 – 4.2 102 = (58-4.2) 102 = 53.8 102

Significant Figures 

These are the meaningful digits that are known with certainty. The uncertain digits can be written as 1, where there are some certain digits and 1 is an estimated digit. For example, in 50.7 kg, 50 is a certain number while 7 is an uncertain digit. There are some rules regarding significant figures –

1. Except zero, all the digits are significant, e.g., 659
2. Two zero between non zero numbers are significant, e.g., 3.008
3. Zero to the right of the decimal are significant, e.g., 0.50
4. Zero to the left of the non-zero number is not significant, e.g., 0.05

Dimensional Analysis

It is a method that is used to convert units from one system to another. For example, how many minutes in 2 days.

1 hr= 60 minutes 1 day = 24hrs ; 2 days = 48 hrs; 2days = 48*60= 2880 minutes

Laws of Chemical combinations

There are five laws of chemical combinations. They are as follows:

1. Law of Conservation of Mass
2. Law of Definite Proportions
3. Avogadro’s Law
4. Law of Multiple Proportions
5. Gay Lussac’s Law of Gaseous Volumes

DALTON’S ATOMIC THEORY

Dalton’s atomic theory was published in 1808 by John Dalton under ‘A New System of Chemical Philosophy’ theory. His theory explains the laws of chemical combinations. 

ATOMIC AND MOLECULAR MASSES

Atomic mass can be defined as a quantity of matter contained in an atom, whereas molecular mass is a sum of atomic masses of an element in molecules.

MOLE CONCEPT AND MOLAR MASSES 

The mass of 1 mole of the substance is the molar mass of that substance. One mole contains exactly 6.022× 1023 elementary entities. Mole (mol) is the SI unit of the amount of a substance.

PERCENTAGE COMPOSITION

Mass% of an element = mass of an element in the compound 100 molar mass of the compound 

Conclusion

Some basic concepts in chemistry include matter, its nature, properties and measurements, laws of chemical combinations, etc. Matter is a basic concept of chemistry and has two types of properties. The SI unit is a universal acceptable measurement system. This study material of some basic concepts in chemistry must have helped to understand the basic concepts in chemistry and the other topics that come under it, such as matter, dimensional analysis, etc.