NEET Chemistry syllabus has broadly classified into 3 categories – Physical, Organic, and Inorganic. This subject can be considered as the scoring out of the other subjects, which can help the candidates to achieve a standing position in the all India entrance exam. NEET Study Notes for Basic Concepts of Chemistry will help you get an idea about very basic concepts like Dalton Theory, Mole, Molarity etc. Check NEET Chemistry Syllabus

Read the article to know more about the basic concepts to score good marks in NEET 2021. 

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Dalton’s Atomic Theory

• Dalton’s theory is considered to be the first one to complete the attempt successfully to describe all the matter in terms of the atomic configuration and their corresponding properties.
• This theory is based on the law of conservation of mass and law of constant composition.
• Law of conservation of mass – mass can never be created nor can be destroyed.

The theory is comprised of 4 parts which have been modified in time with the constant research works:

• 1st part – all the matter is made of atoms, which cannot be further divided.
• 2nd part – all atoms of the given element are identical in mass and properties.
• 3rd part – all the compounds are the combination of two or more different types of atoms.
• 4th part – a chemical reaction taking place is the simple rearrangement of atoms.

Sample Question

Ques: 20.0 g of a magnesium carbonate sample decomposes on heating to give carbon dioxide and 8.0 g magnesium oxide. What will be the percentage purity of magnesium carbonate in the sample? (Atomic weight of Mg = 24)

1. 75
2. 96
3. 60
4. 84

Ans: (4)

Must Read: 

• NEET Study notes Ray Optics
• NEET Study notes for Chemical Bonding

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Stoichiometry, Mole, Molarity

• Stoichiometry is the study that deals with the relationship and the balance of the reactants and the products involved in the reaction.
• Mole –1 mole is defined as the amount of substance which contains as many particles as there are atoms in exactly 12 gm of the C-12 isotope of carbon.
• Molar mass – the mass of one mole of a substance in grams is termed as the molar mass.
• Molarity (M) - Number of moles of a solute present in per unit volume of solution.
• M = mol of solute / L of solution
• Molality (m) - Number of moles of a solute present in one kilogram of a solvent.
• Normality (N) - Number of gram equivalents of a solute present in per unit volume of solution.
• Mole fraction - Ratio of the number of moles of a particular component to the total number of moles of the solution.
• Mass per cent or weight per cent (w / w %) - Gram of solute present in 100 gram of solution.
• Volume by volume per cent (v / v %) - mL of solute present in 100 mL of solution.
• Weight by volume per cent (w / v %) - Gram of solute present in 100 mL of solution.
• Empirical formulae – the empirical formulae is the simplest ratio of the elements that make up the compound, while the actucal number off the atoms may vary from that of the original formulae. The molecular formula may be the empirical formula in some cases.
• Limiting reactant – The limiting reactant is the one that gets consumed first when the chemical reaction is started, hence controlling how much product should be formed.

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Previous Year Solved Sample Questions

Ques: If Avogadro number Na, is changed from 6.022 x 1023 mol to 6.022 x 1020 mol this would change

1.  the definition of mass in units of grams
2. the mass of one mole of carbon
3. the ratio of chemical species to each other in a balanced equation
4. the ratio of elements to each other in a compound

Ans: B

Ques: What is the mass of precipitate formed when 50 ml. of 16.9% solution of AgNO3 is mixed with 50 ml of 5.8% NaCl solution? (Ag = 107.8, N = 14, O = 16, Na=23,CI=35.5)

1. 28 g
2. 3.5 g
3. 7 g
4. 14 g

Ans: C

Ques: What is the atomic weight of an element X for which a sample containing 1.58×1022 atoms weighs 1.05 g?

1. 28 g
2. 20 g
3. 40 g
4. 23 g

Ans: C

Ques: How many grams of CaO are required to neutralize 852 g of P4O10?

1. 1008 g
2. 108 g
3. 1800 g
4. 3600 g

Ans: A

Ques: A hydrocarbon contains 10.5 g carbon and 1g hydrogen. Its 2.4 g has 1 L volume as 1 atm and127oC. Hydrocarbon is

1. C6H7
2. C6H6
3. C5H6
4. C6H6

Ans: A

Ques: It is known that atoms have proton, neutron, electron and nucleus. If the mass of neutron assumed to be half of its original value whereas that of proton is assumed to be twice the original value, then the atomic mass of 6C14 will be

1. 14.3% less than original value
2. 14.3% greater than original value
3. 28.6% less than original value
4. 28.6% greater than original value

Ans: A

Ques: 2.76 g of silver carbonate on being strongly heated yields a residue weighing

1. 2.15 g
2. 2.48 g
3. 2.32 g
4. 2.64 g

Ans: A

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Some tricks/tips to solve the Questions on the exam day

Here we are providing you with some tips on how to solve and what are the tricks to solve the questions on the day of NEET exam, so as to avoid any unnecessary clash or time management problems.

• On exam day, Start by attempting easy questions - You will be bound by time to solve maximum number of questions, so try to answer the questions which you feel are easy and can be completed in time. This will help you save time for the topics which you have found difficult and give more time to those questions to avoid any mistakes in hurry.
• Start giving mocks at the same time of exam - Since the date and time of the examination is available, you can start making your schedule according to the day of exam. Start giving mock tests at the same time at which you have exam on the D-Day. This will help you body and mind ready for the exam day.
• Read questions carefully - Many students, although knowing the answer make mistakes while solving them as they do not read the questions fully / properly. Give importance to the units and the numbers to avoid any mistakes.
• Put Values to narrow down your options - In some questions, equations will be given in options. Solving these equations and checking each of them consumes a lots of time.
• Do not panic - In case you are running out of time, do not panic, and try to stay as calm as you might make mistakes in solving the questions which you know well resulting in downgrading the overall results. Also, while solving, if you find any difficulty in solving the particular question, leave it and move on to the next one and come back to that question in the end (if you have extra time).

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