Important Laws In Chemistry and Their Formulas

Chemistry is present all over, in our daily lives – from the air, we breathe to the food we eat, chemistry involves almost everything. But we don’t sense all of the things that are happening around us. Since thousands of years back, chemists have been observing nature and the matter around us which comes up with different laws of chemistry which had laid the foundation for us to understand in detail about the chemistry of our universe.

Major Laws In Chemistry

I. Law of conservation of mass

The Law of conservation of mass is the most foundational and fundamental conception of chemistry. The Law of conservation of mass asserts as follows – “The amount of matter contained in a chemical reaction continues to remain the same before and after the reaction”.

II. Law of conservation of energy

The Law of conservation of energy is the initial basic Law which relates to the thermodynamic system. The Law states that- The total energy of a chemical reaction system preserves itself when it is isolated from the surroundings.

III. Boyle’s Law

Boyle’s Law derives its name from the Boyle – Mariotte law or Mariotte’s Law. Boyle’s Law asserts that- The universal pressure employed by a specified mass of an ideal gas is inversely proportional to the volume it absorbs provided the temperature and amount of gas remain constant within a closed system.

PV = C

When the pressure increases the volume decreases. When volume increases, the pressure decreases. Hence the equation made is :

P1V1 = P2V2 = P3V3

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IV. Charles Law

Also known as the “Law of volumes“. Charles’s Law is a probing gas law that states how gases favour expanding when it is heated. The Law states that- When the pressure on a specimen dry gas is kept constant, the Kelvin temperature and the volume gets directly related.

V / T = C

when the volume increases, the temperature also increases and vice-versa.

And hence initial and final volumes and temperatures under constant pressure can be calculated as:

V1 / T1 = V2 / T2 = V3 / T3

V. Dalton’s Law of partial pressure

Dalton’s Law of partial pressures asserts that- In a combination of non-reacting gases, the total pressure exerted equals to the sum of the partial pressures of each gas.

P1V1 / T1 = P2V2 / T2 = P3V3 / T3

P total = Pa + Pb + Pc + …

or

= naRT / V + nbRT / V + ncRT / V + …

or

P total = (na+ nb+ nc+ … )RT / V

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VI. Avogadro’s Law

This specific Avogadro’s Law was established in 1811 by Amedeo Avogadro. Avogadro’s Law specifies that: Equal volumes of all gases have the same number of molecules at the same temperature and pressure.

V / n = C

This means that the volume-amount fraction will always be the same value if the pressure and temperature are constant.

V1/ n1 = V2 / n2 = V3 / n3

P1V1 / T1 = P2V2 / T2 = P3V3 / T3

VII. Ideal Gas Law

The Ideal Gas Law states that- If the volume (V) absorbed by n moles of agas has a pressure (P) at a temperature (T) in Kelvin, the equation between these variables, i.e. V, P, and T is:

PV = nRT

VIII. Periodic Law

The Periodic Law was autonomously evolved by “Dmitri Mendeleev” and “Lothar Meyer” in 1869. The Periodic Law asserts that-By aligning the elements are in order of increasing atomic number, the physical and chemical properties of the elements reoccur in a systematic and expected way.

It signifies that while arranging the elements are in the alignment of their increasing atomic numbers; the elements were having the same properties occur at regular intervals or periodically. Hence, the elements fall in certain specific groups and results in an arrangement known as the modern periodic table of elements.

IX. Laws of thermodynamics

The 4 laws of thermodynamics explain, “The basic physical quantities identifying the thermodynamic systems at thermal equilibrium”. The laws draw out how these quantities behave in various situations and outlaw specific phenomena. There are four laws of thermodynamics namely-Zeroth, First, Second, and the Third Laws of thermodynamics.

X. Faraday’s Law

1. A voltage, i.e. emf, is “induced” in the coil, if there is any change in its magnetic field. Faraday’s Law clarifies this.

Faraday’s Law affirms that: The quantity of a substance released at an electrode is directly proportional to the quantity of the electricity traveled.

XI. Henry’s Law

Henry’s Law is a gas law that was drawn up by the British chemist, “William Henry” in 1803. It asserts that – The amount of a given gas dissolved in a given volume of liquid is directly proportional to the partial pressure of the gas in equilibrium with that specific liquid, at a constant temperature.

P ∝ C (or) P = kH.C

Where,

• ‘P’ indicates the partial pressure of the gas in the atmosphere above the liquid.
• ‘C’ indicates the concentration of the dissolved gas.
• ‘kH’ is Henry’s law constant of the gas.