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Which of the following molecule has highest percentage of oxygen by mass ?

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Important Questions on Some Basic Concepts of Chemistry

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Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition, Empirical Formula and Molecular Formula

1 g

of an organic compound containing

C

and

H

, on complete combustion produced

3.04 g

{CO}_{2}

and

1.53 g

H_{2} O

. Find the approximate percentage composition of

C

and

H

in the compound.

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition, Empirical Formula and Molecular Formula

The percentage composition of carbon by mole in methane is:

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Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition, Empirical Formula and Molecular Formula

Calculate the percentage by weight of oxygen in a mole of water?

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Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition, Empirical Formula and Molecular Formula

Among the following nitrogen compounds, which one has lowest percentage of nitrogen?

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Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition, Empirical Formula and Molecular Formula

Mass % of carbon in ethanol is

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition, Empirical Formula and Molecular Formula

In the crystalline solid

M S O_{4} \cdot n {II}_{2} O

of molar mass

250 g {mol}^{- 1},

the percentage of anhydrous salt is

64

by weight. The value of

n

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Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition, Empirical Formula and Molecular Formula

Complex A has a composition of

H_{12} O_{6} {Cl}_{3} C r

. If the complex on treatment with conc.

H_{2} {SO}_{4}

loses

13.5 %

of its original mass, the correct molecular formulas of

A

is:
[Given : atomic mass of

C r = 52

amu and

Cl = 35

amu]

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition, Empirical Formula and Molecular Formula

Calculate the percentage of fluorine in sodium aluminium fluoride

[{Na}_{3} {AlF}_{6}]

to the nearest whole number. [Atomic mass:

Na = 23, Al = 27, F = 19

]

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition, Empirical Formula and Molecular Formula

1.85 g

sample of an arsenic-containing pesticide was chemically converted to

{AsO}_{4}^{3 -}

(atomic mass of

As = 74.9

) and titrated with

{Pb}^{2 +}

to form

{Pb}_{3} {({AsO}_{4})}_{2}

. If

20 mL of 0.1 M {Pb}^{2 +}

is required to reach the equivalence point, the mass percentages of arsenic in the pesticide sample is closest to

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition, Empirical Formula and Molecular Formula

One mole of one of the sodium salts listed below, having carbon content close to

14.3 %

produces

1

mole of carbon dioxide upon heating

(Atomic masses : Na = 23, H = 1, C = 12, O = 16)

. The salt is

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition, Empirical Formula and Molecular Formula

In a non-stoichiometric sample of cuprous sulphide, with the composition ${Cu}_{1.8} S,$ cupric ions are also present in the lattice. What mole percent of ${Cu}^{2 +}$ is present in the copper content of the crystal?

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Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition, Empirical Formula and Molecular Formula

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)

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition, Empirical Formula and Molecular Formula

Calculate the mass percentage of benzene

(C_{6} H_{6})

and carbon tetrachloride

({CCl}_{4})

38 g

of benzene is dissolved in

122 g

of carbon tetrachloride

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Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition, Empirical Formula and Molecular Formula

A metal

M

(specific heat

0.16

) forms a metal chloride with

65 %

chlorine present in it. The formula of the metal chloride will be

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition, Empirical Formula and Molecular Formula

A metal chloride contains $55.0 %$ of chlorine by weight. $100 mL$ vapours of the metal chloride at STP weigh $0.57 g$ . The molecular formula of the metal chloride is

(Given: Atomic mass of chlorine is $35.5 u$ )

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition, Empirical Formula and Molecular Formula

Calculate the percentage of sodium in sodium aluminium fluoride

[{Na}_{3} {AlF}_{6}]

to the nearest whole number. [Atomic mass:

Na = 23, Al = 27, F = 19

]

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition, Empirical Formula and Molecular Formula

Calculate the percentage of aluminium in sodium aluminium fluoride

[{Na}_{3} {AlF}_{6}]

to the nearest whole number. [Atomic mass:

Na = 23, Al = 27, F = 19

]

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition, Empirical Formula and Molecular Formula

An organic compound contains

C, H

and

S

. The minimum molecular weight of the compound containing

8 %

Sulphur is

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition, Empirical Formula and Molecular Formula

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

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition, Empirical Formula and Molecular Formula

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

Which of the following molecule has highest percentage of oxygen by mass ?

Important Questions on Some Basic Concepts of Chemistry

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