45 . 4 L of dinitrogen reacted with 22 . 7 L of dioxygen and 45 . 4 L of nitrous oxide was formed. The reaction is given below: 2 N 2 ( g ) + O 2 ( g ) → 2 N 2 O ( g ) Which law is being obeyed in this experiment? Write the statement of the law?

Gases are reacting together to form gaseous products. Ratios of volumes of gases: N 2 : O 2 : N 2 O = 45 . 4 : 22 . 7 : 45 . 4 = 2 : 1 : 2 Gay Lussac’s law of gaseous volumes is being obeyed in this experiment. According to this law, the ratio between the volumes of gaseous reactants and products can be expressed in simple whole numbers at the same temperature and pressure.

Calculate the average atomic mass of hydrogen using the following data: Isotope % Natural abundance Molar mass 1 H 99 . 985 1 2 H 0 . 015 2

The average atomic mass of an element is the sum of the masses of its isotopes, each multiplied by its natural abundance. Average atomic mass = ( Natural abundance of 1 H × molar mass ) + ( Natural abundance of 2 H × molar mass of 2 H ) 100 = 99 . 985 × 1 + 0 . 015 × 2 100 = 99 . 985 + 0 . 030 100 = 100 . 015 100 = 1 . 00015 u

Hydrogen gas is prepared In the laboratory by reacting dilute HCl with granulated zinc. Following reaction takes place. Zn + 2 HCl → ZnCl 2 + H 2 Calculate the volume of hydrogen gas liberated at STP when 32 . 65 g of zinc reacts with HCl . 1 mol of a gas occupies 22 . 7 L volume at STP; atomic mass of Zn = 65 . 3 u .

The given reaction is, Zn + 2 HCl → ZnCl 2 + H 2 From stoichiometry, One mole zinc reacts with two moles of HCl to produce one mole of zinc chloride and one mole of hydrogen gas. 65 . 3 g of Zn reacts with HCl to form 22 . 7 L of H 2 ( g ) ∴ 32 . 65 g of Zn at STP reacts with HCl to form = 22 . 7 × 32 . 65 65 . 3 = 11 . 35 L .

E M B I B E

NCERT Exemplar Chemistry - Class 11>Chapter 1 - Some Basic Concepts of Chemistry>Short Answer Type>Q 23

EASY

11th CBSE

IMPORTANT

Earn 100

What will be the mass of one atom of $C - 12$ in grams?

Important Questions on Some Basic Concepts of Chemistry

EASY

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 1 - Some Basic Concepts of Chemistry>Short Answer Type>Q 24

How many significant figures should be present in the answer of the following calculations?

$\frac{2.5 \times 1.25 \times 3.5}{2.01}$

EASY

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 1 - Some Basic Concepts of Chemistry>Short Answer Type>Q 25

What is the symbol for SI unit of mole? How is the mole defined?

EASY

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 1 - Some Basic Concepts of Chemistry>Short Answer Type>Q 26

What is the difference between molarity and molality?

EASY

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 1 - Some Basic Concepts of Chemistry>Short Answer Type>Q 27

Calculate the mass percent of calcium, phosphorus and oxygen in calcium phosphate

{Ca}_{3} ({PO}_{4})_{2} .

EASY

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 1 - Some Basic Concepts of Chemistry>Short Answer Type>Q 28

45.4 L

of dinitrogen reacted with

22.7 L

of dioxygen and

45.4 L

of nitrous oxide was formed. The reaction is given below:

2 N_{2} (g) + O_{2} (g) \to 2 N_{2} O (g)

Which law is being obeyed in this experiment? Write the statement of the law?

MEDIUM

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 1 - Some Basic Concepts of Chemistry>Short Answer Type>Q 29

If two elements can combine to form more than one compound, the masses of one element that combine with a fixed mass of the other element, are in whole number ratio.

(a) Is this statement true?

(b) If yes, according to which law?

(c) Give one example related to this law.

EASY

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 1 - Some Basic Concepts of Chemistry>Short Answer Type>Q 30

Calculate the average atomic mass of hydrogen using the following data:

Isotope	$%$ Natural abundance	Molar mass
$^{1} H$	$99.985$	$1$
$^{2} H$	$0.015$	$2$

EASY

11th CBSE

IMPORTANT

NCERT Exemplar Chemistry - Class 11>Chapter 1 - Some Basic Concepts of Chemistry>Short Answer Type>Q 31

Hydrogen gas is prepared In the laboratory by reacting dilute $HCl$ with granulated zinc. Following reaction takes place.

$Zn + 2 HCl \to {ZnCl}_{2} + H_{2}$

Calculate the volume of hydrogen gas liberated at STP when $32.65 g$ of zinc reacts with $HCl$ . $1 mol$ of a gas occupies $22.7 L$ volume at STP; atomic mass of $Zn = 65.3 u .$