5 moles of A B 2 weigh 125 × 10 - 3 k g and 10 moles of A 2 B 2 weigh 300 × 10 - 3 k g . The molar mass of A ( M A ) and molar mass of B ( M B ) in k g m o l - 1 are:

M A = 5 × 10 - 3 and M B = 10 × 10 - 3

M A = 25 × 10 - 3 and M B = 50 × 10 - 3

M A = 50 × 10 - 3 and M B = 25 × 10 - 3

M A = 10 × 10 - 3 and M B = 5 × 10 - 3

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Silver salt of certain Organic acid with atomic ratio $C : H : O$ as $2 : 3 : 2$ contains 65.06% of silver. If each molecule of acid has two ionisable H atoms, the formula of the acid

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Important Questions on Some Basic Concepts of Chemistry

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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

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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

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}

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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

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

An organic compound contains

C, H

and

S

. The minimum molecular weight of the compound containing

8 %

Sulphur is

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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

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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]

HARD

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

In Carius method of estimation of halogens,

250 mg

of an organic compound gave

141 mg AgBr

. What is the percentage of bromine in the compound (atomic mass of

Ag = 108

and atomic number of

Br = 80

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

The percentage composition of carbon by mole in methane is:

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

5

moles of

A B_{2}

weigh

125 \times 10^{- 3} k g

and

10

moles of

A_{2} B_{2}

weigh

300 \times 10^{- 3} k g

. The molar mass of A

(M_{A})

and molar mass of

B (M_{B})

k g {m o l}^{- 1}

are:

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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

]

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

The number of water molecules is maximum in

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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

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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

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 $162 g {mol}^{- 1}$ .

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

The percentage of nitrogen by mass in ammonium sulphate is closest to (atomic masses H = 1, N = 14, O = 16, S = 32)

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

A sample of a hydrate of barium chloride weighing 61 g was heated until all the water of hydration is removed. The dried sample weighed 52 g. The formula of the hydrated salt is: (atomic mass, Ba = 137 amu, Cl = 35.5 amu)

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

In which case the number of molecules of water maximum?

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

Suppose the elements

X

and

Y

combine to form two compounds

X Y_{2}

and

X_{3} Y_{2}

. When

0.1 mole

X Y_{2}

weighs

10 g

and

0.05 mole

X_{3} Y_{2}

weighs

9 g

, the atomic weights of

X

and

Y

are

MEDIUM

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

The amount of sugar

(C_{12} H_{22} O_{11})

required to prepare

2 L

of its

0 .1 M

aqueous solution is:

Silver salt of certain Organic acid with atomic ratio C :H :O as 2 :3 :2 contains 65.06% of silver. If each molecule of acid has two ionisable H atoms, the formula of the acid

Important Questions on Some Basic Concepts of Chemistry

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Silver salt of certain Organic acid with atomic ratio $C : H : O$ as $2 : 3 : 2$ contains 65.06% of silver. If each molecule of acid has two ionisable H atoms, the formula of the acid