Some Basic Concepts of Chemistry

In the medical entrance test NEET, there can be 1 to 3 questions from this chapter. Some year, the Chemistry section of NEET has only one question from this chapter and in some other years, there can be 3 questions.

The following are the key concepts of this chapter: Compound, Elements, Rules, Law of conservation of mass, Addition and Subtraction, Atomic Mass, Law of multiple proportions, and Molecular Mass.

As the name suggests, the first chapter of the NCERT Class 11 Chemistry introduces various basic concepts of chemistry, such as the definition and importance of chemistry, atomic matter and molecular masses, the mole concept, laws of chemical combination, empirical, stoichiometry, and molecular formulas. It also includes the concepts of molarity and molality.

$\frac{0.02858*0.112}{0.5702}=0.0561$

20 g of 20% CaCO? = 20 * (20/100) = 4 g CaCO?
CaCO? (100 g) - (1200 K)-> CaO + CO? (44 g)
According to the reaction,
100 g of CaCO? → 44 g of CO?
4 g CaCO? → (4*44)/100 g of CO?
= 1.76 g of CO?

Dihedral angle (D.A.) of least stable conformer of ethane = 0°

D.A. = 0°
(Eclipsed)

Number of mole of $\mathrm{X}=\frac{6.022*{10}^{22}}{6.022*{10}^{23}}=\frac{10}{\text{Molar mass of}\mathrm{X}}$

So molar mass of $X=100\mathrm{g}$

Molarity $=\frac{5}{100*2}=0.025\mathrm{M}$

Ans. $=0.025\mathrm{M}$

$\mathrm{M}=25*{10}^{-3}$

So $P=25$