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A solid element reacts with insufficient oxygen and the reaction shows no change in volume of gaseous phase. If vapour density of gaseous product is 32, the equivalent weight of element would be :

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Important Questions on Some Basic Concepts of Chemistry

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Atomic and Molecular Mass

The molecular formula of a commercial resin used for exchanging ions in water softening is

C_{8} H_{7} S O_{3} N a

(molecular weight = 206)

. What would be the maximum uptake of

C a^{2 +}

ions by the resin if expressed in

mol

per

gm

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Atomic and Molecular Mass

Two elements

A

and

B

which form

0.15

moles of

A_{2} B

and

{AB}_{3}

type compounds. If one mole of each

A_{2} B

and

{AB}_{3}

weigh equally, then the atomic weight of

A

is____times of atomic weight of

B

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Atomic and Molecular Mass

Which symbol replaced the unit of atomic mass, amu?

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Atomic and Molecular Mass

Galena (an ore) is partially oxidized by passing air through it at high temperature. After some time, the passage of air is stopped, but the heating is continued in a closed furnace such that the contents undergo self-reduction. The weight (in $kg$ ) of $Pb$ produced per $kg$ of $O_{2}$ consumed is ____. (Atomic weights in $g {mol}^{- 1} : O = 16, S = 32, Pb = 207$ )

Give the answer to the nearest integer value.

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Atomic and Molecular Mass

One mole of dioxygen gas at

STP

is equal to

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Atomic and Molecular Mass

For the following reaction, the mass of water produced from

445 g

C_{57} H_{110} O_{6}

is:

2 C_{57} H_{110} O_{6} (s) + 163 O_{2} (g) \to 114 {CO}_{2} (g) + 110 H_{2} O (l)

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Atomic and Molecular Mass

Consider an imaginary ion

{}_{22}^{48}X^{3 -}

. The nucleus contains '

a

%

more neutrons than the number of electrons in the ion. The value of '

a

' is

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Atomic and Molecular Mass

A gaseous hydrocarbon on combustion gives $0.72 g$ of water and $3.08 g$ ${CO}_{2}$ . What is the empirical formula of the hydrocarbon?

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Atomic and Molecular Mass

The unit of atomic mass,

amu

is replaced by

u

, here

u

stands for

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Atomic and Molecular Mass

What will be the mass of one atom of

{}^{12}C

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Atomic and Molecular Mass

The ammonia is prepared by treating ammonium sulphate with calcium hydroxide is completely used by ${NiCl}_{2} \cdot 6 H_{2} O$ to form a stable coordination compound. Assume that, both the reactions are $100 %$ completed. If $1584 g$ of ammonium sulphate and $952 g$ of ${NiCl}_{2} \cdot 6 H_{2} O$ are used in the preparation, the combined weight (in grams) of gypsum and the nickel ammonia coordination compound produced is ____.

Atomic weights in $g {mol}^{- 1}$ :

$H = 1; N = 14 O = 16; S = 32 Cl = 35 .5; Ca = 40 Ni = 59$

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Atomic and Molecular Mass

3 g

of acetic acid is added to

250 m L

0.1 M H C l

and the solution made up to

500 m L

. To

20 m L

of this solution

\frac{1}{2} m L

5 M N a O H

is added. The

p H

of the solution is ________
[Given:

p K a

of acetic acid

= 4.75,

molar mass of acetic acid

60 g / m o l, \log 3 = 0.4771

, Neglect any changes in volume]

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Atomic and Molecular Mass

20.0 g of a magnesium carbonate sample decomposes on heating to give carbon dioxide and 8.0 g magnesium oxide. What will be the percentage purity of magnesium carbonate in the sample?

(Atomic weight: Mg = 24)

HARD

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Atomic and Molecular Mass

A mixture of

100 m mol

Ca {(OH)}_{2}

and

2 g

of sodium sulphate was dissolved in water and the volume was made up to

100 mL .

What is the mass of calcium sulphate formed and the concentration of

{OH}^{-}

in resulting solution, respectively? (Molar mass of

Ca {(OH)}_{2}, {Na}_{2} {SO}_{4}

and

{CaSO}_{4}

are

74, 143

and

136 g {mol}^{- 1},

respectively;

K_{sp}

Ca {(OH)}_{2} is 5 .5 \times 10^{- 6}

)

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Atomic and Molecular Mass

What is the mass of the precipitate formed when 50 mL of

16.9 %

solution of

A g N O_{3}

is mixed with 50 mL of

5.8 %

NaCl solution?

(Ag = 107.8, N = 14, O = 16, Na = 23, Cl = 35.5)

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Atomic and Molecular Mass

1

gram of a carbonate

(M_{2} {CO}_{3})

on treatment with excess

HCl

produces

0.01186

moles of

{CO}_{2}

. The molar mass of

M_{2} {CO}_{3}

{gmol}^{- 1}

is:

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Atomic and Molecular Mass

In the following reaction:

$A + 2 B + 3 C ⇌ A B_{2} C_{3}$
$6.0 g$ of $A$ , $6.0 \times 10^{23}$ atoms of $B$ and $0.036 mol$ of $C$ reacted and formed $4.8 g$ of compound $A B_{2} C_{3}$ . If the atomic mass of $A$ and $C$ are $60$ and $80 amu$ , respectively. What is the atomic mass of $B$ in $amu$ ? (Avogadro number $= 6 \times 10^{23}$ )

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Atomic and Molecular Mass

Calculate mass of

3.01 \times 10^{24}

atoms of an element having atomic mass

21.13

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Atomic and Molecular Mass

The average molar mass of chlorine is

35.5 g {mol}^{- 1}

. The ratio of

{}^{35}{Cl}

{}^{37}{Cl}

in naturally occurring chlorine is close to :

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Atomic and Molecular Mass

In a certain mass spectrometer, an ion beam passes through a velocity filter consisting of mutually perpendicular fields E and B. The beam then enters a region of another magnetic field

B^{'}

, perpendicular to the beam. The radius of curvature of the resulting ion beam is proportional to

A solid element reacts with insufficient oxygen and the reaction shows no change in volume of gaseous phase. If vapour density of gaseous product is 32, the equivalent weight of element would be :

Important Questions on Some Basic Concepts of Chemistry

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