Some Basic Concepts of Chemistry

Chlorophyll extracted form the crushed green leaves was dissolved in water to make 2 L solution of Mg of concentration 48 ppm. The number of atoms of Mg in this solution is x × 10²⁰ atoms. The value of x is _____________. (Nearest Integer)

(Given : Atomic mass of Mg is 24 g mol^-1; N_A = 6.02 × 10²³ mol^-1)

A sample of 0.125g of an organic compound when analyzed by Duma’s method yields 22.78 mL of nitrogen gas collected over KOH solution at 280 K and 759 mm Hg. The percentage of nitrogen in the given organic compound is__________. (Nearest integer)

[Given: (a) The vapour pressure of water of 280K is 14.2mm Hg

(b) R = 0.082 L atm K^-1 mol^-1]

2L of 0.2 M H₂SO₄ is reacted with 2L of 0.1 M NaOH solution, the molarity of the resulting product Na₂SO₄ in the solution is_________ millimolar (Nearest integer)

The mass of ammonia in grams produced when $2.8\mathrm{k}\mathrm{g}$ of dinitrogen quantitatively reacts with $1\mathrm{k}\mathrm{g}$ of dihydrogen is(Mole Concept)

<!-- [if gte mso 9]><xml> </xml><![endif]-->  $N_{2\left(g\right)}+3H_{2\left(g\right)}?2N{H}_{3\left(g\right)}$

20g     5g

Consider the above reaction, the limiting reagent of the reaction and number of moles of NH₃ formed respectively are:

116 g of a substance upon dissociation reaction yields 7.5 g of hydrogen 60 g of oxygen and 48.5 g of carbon. Given that the atomic masses of H, O and C are 1, 16 and 12, respectively. The data agrees with how many formulae of the following?

(a) CH₃COOH                                  (b) HCHO                          (c) CH₃OOCH₃                            (d) CH₃CHO

Assertion (A) : Combustion of 16 g of methane gives 18 g of water.

Reason (R) : In the combustion of methane, water is one of the products. 

(i) Both A and R are true but R is not the correct explanation of A.

(ii) A is true but R is false.

(iii) A is false but R is true.

(iv) Both A and R are false.

Assertion (A) : Significant figures for 0.200 is 3 where as for 200 it is 1.

Reason (R) : Zero at the end or right of a number are significant provided they are not on the right side of the decimal point. 

(i) Both A and R are true and R is correct explanation of A.

(ii) Both A and R are true but R is not a correct explanation of A.

(iii) A is true but R is false.

(iv) Both A and R are false.

Assertion (A) : One atomic mass unit is defined as one twelfth of the mass of one carbon-12 atom.

Reason (R) : Carbon-12 isotope is the most abundunt isotope of carbon and has been chosen as standard.

(i) Both A and R are true and R is the correct explanation of A.

(ii) Both A and R are true but R is not the correct explanation of A.

(iii) A is true but R is false.

(iv) Both A and R are false.

In the following questions a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below each question.

Assertion (A): The empirical mass of ethene is half of its molecular mass.

Reason (R): The empirical formula represents the simplest whole number ratio of various atoms present in a compound.

(i) Both A and R are true and R is the correct explanation of A.

(ii) A is true but R is false.

(iii) A is false but R is true.

(iv) Both A and R are false