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Elements $X$ and $Y$ can combine to form two different compounds. If $1.6 g$ of $X$ reacts with exactly $1.6 g$ of $Y$ , the compound produced has formula ${XY}_{2}$ . However under different condition, $2.4 g$ of $X$ will react with $1.6 g$ of $Y$ to form a second compound, whose empirical formula is-

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Important Questions on Some Basic Concepts of Chemistry

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Empirical and Molecular Formulae

A pure compound contains

2.4 g

C, 1.2 \times 10^{23}

atoms of

H, 0.2

moles of oxygen atoms. Its empirical formula is

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Empirical and Molecular Formulae

An organic compound contains

24 %

carbon,

4 %

hydrogen and remaining chlorine. Its empirical formula is

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Empirical and Molecular Formulae

In a compound

C, H

and

N

are present in

9 : 1 : 3.5

by weight. If molecular weight of compound is

108

, the molecular formula of compound is

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Empirical and Molecular Formulae

Compound $A$ contains $8.7 %$ Hydrogen, $74 %$ Carbon and $17.3 %$ Nitrogen. The molecular formula of the compound is, Given : Atomic masses of $C, H$ and $N$ are $12, 1$ and $14$ amu respectively.

The molar mass of the compound $A$ is $162 g {mol}^{- 1}$ .

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Empirical and Molecular Formulae

A compound with molecular mass

180

is acylated with

{CH}_{3} COCl

to get a compound with molecular mass

390

. The number of amino groups presents per molecule of the former compound is

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Empirical and Molecular Formulae

An organic compound contains

60 % C; 4.48 % H

and

35.5 % O .

Its empirical formula is

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Empirical and Molecular Formulae

The empirical formula and molecular mass of a compound are

{CH}_{2} O

and

180 g

respectively. The molecular formula of the compound will be

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Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Empirical and Molecular Formulae

If the Thomson model of the atom was correct, then the result of Rutherford's gold foil experiment would have been:

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Empirical and Molecular Formulae

A compound has the following composition by weight;

N a = 18.60 %, S = 25.80 %, H = 4.02 %

and

O = 51.58 %

Assuming that all the hydrogen atoms in the compound are part of water of crystallization, the correct molecular formula of the compound is

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Empirical and Molecular Formulae

1.25 g of a metal (M) reacts with oxygen completely to produce 1.68 g of metal oxide. The empirical formula of the metal oxide is [Molar mass of M and O are

69.7 g m o l^{- 1}

and

16.0 g m o l^{- 1}

, respectively]

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Empirical and Molecular Formulae

The elemental analysis of an organic compound gave

C : 38.71 %, H : 9.67 %

. What is the empirical formula of the compound?

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Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Empirical and Molecular Formulae

56.0 L

of nitrogen gas is mixed with excess of hydrogen gas and it is found that

20 L

of ammonia gas is produced, The volume of unused nitrogen gas is found to be_____

L

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Empirical and Molecular Formulae

To check the principle of multiple proportions, a series of pure binary compounds $(P_{m} Q_{n})$ were analysed and their composition is tabulated below. The correct option(s) is(are)

Compound	Weight $%$ of $P$	Weight $%$ of $Q$
$1$	$50$	$50$
$2$	$44.4$	$55.6$
$3$	$40$	$60$

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Empirical and Molecular Formulae

An organic compound contains

80 %

(by wt.) carbon and remaining percentage of hydrogen. The right option for the empirical formula of this compound is: [Atomic wt. of

C

12

and of

H

1

]

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Empirical and Molecular Formulae

Which of the following conclusions could not be derived from Rutherford's

α

-particle scattering experiment:

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Empirical and Molecular Formulae

The statement related to law of definite proportions is

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Empirical and Molecular Formulae

Among the following pairs of compounds, the one that does not illustrate the law of multiple proportions, is

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Empirical and Molecular Formulae

The ratio of mass percent of

C and H

of an organic compound

(C_{X} H_{Y} O_{Z})

6 : 1 .

If one molecule of the above compound

(C_{X} H_{Y} O_{Z})

contains half as much oxygen as required to burn one molecule of compound

C_{X} H_{Y}

completely to

{CO}_{2}

and

H_{2} O .

The empirical formula of the compound

C_{X} H_{Y} O_{Z}

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Empirical and Molecular Formulae

Which of the following have same number of significant figures?
(A)

0.00253

(B)

1.0003

(C)

15.0

(D)

163

Choose the correct answer from the options given below

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Empirical and Molecular Formulae

Which of the following is an example of Law of multiple proportion?

Elements X and Y can combine to form two different compounds. If 1.6 g of X reacts with exactly 1.6 g of Y, the compound produced has formula XY2. However under different condition, 2.4 g of X will react with 1.6 g of Y to form a second compound, whose empirical formula is-

Important Questions on Some Basic Concepts of Chemistry

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