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$30 g$ alloy of $Al$ and $Mg$ when heated with excess of dil. $HCl$ forms ${AlCl}_{3}$ and ${MgCl}_{2}$ respectively. If the volume of $H_{2} (g)$ released at NTP is $33.6 L$ , then what is the composition of the alloy?

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Important Questions on Some Basic Concepts of Chemistry

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition of Compounds

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

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition of Compounds

The percentage composition of carbon by mole in methane is:

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition of Compounds

In an estimation of bromine by Carius method,

1.6 g

of an organic compound gave

1.88 g

AgBr

. The mass percentage of bromine in the compound is

\dots . .

(

Atomic mass,

Ag = 108, Br = 80 {gmol}^{- 1}

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition of Compounds

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

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition of Compounds

Mass % of carbon in ethanol is

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition of Compounds

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

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition of Compounds

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 of Compounds

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?

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition of Compounds

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 of Compounds

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 of Compounds

Complete combustion of

750 g

of an organic compound provides

420 g

{CO}_{2}

and

210 g

H_{2} O

. The percentage composition of carbon and hydrogen in organic compound is

15.3

and ______ respectively. (Round off to the Nearest Integer)

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition of Compounds

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 of Compounds

When $0.15 g$ of an organic compound was analyzed using Carius method for estimation of bromine, $0.2397 g$ of $AgBr$ was obtained. The percentage of bromine in the organic compound is _________.(Nearest integer)

[Atomic mass : Silver $= 108,$ Bromine $= 80$ ]

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition of Compounds

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.

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition of Compounds

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 of Compounds

$116 g$ 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. ${CH}_{3} COOH$

B. $HCHO$

C. ${CH}_{3} {OOCH}_{3}$

D. ${CH}_{3} CHO$

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition of Compounds

A protein '

A

' contains

0.30 %

of glycine (molecular weight

75

). The minimum molar mass of the protein '

A

' is____

\times 10^{3} g {mol}^{- 1}

[nearest integer]

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Percentage Composition of Compounds

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 of Compounds

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 of Compounds

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

30 g alloy of Al and Mg when heated with excess of dil. HCl forms AlCl3 and MgCl2 respectively. If the volume of H2(g) released at NTP is 33.6 L, then what is the composition of the alloy?

Important Questions on Some Basic Concepts of Chemistry

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$30 g$ alloy of $Al$ and $Mg$ when heated with excess of dil. $HCl$ forms ${AlCl}_{3}$ and ${MgCl}_{2}$ respectively. If the volume of $H_{2} (g)$ released at NTP is $33.6 L$ , then what is the composition of the alloy?