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An element 'A' have 3 isotopes A²⁴,A²⁸ & A³⁰,if percentage abundance of A²⁴ is 50% then calculate percentage abundance of A²⁸ and A³⁰
(Given : average atomic mass = 26.8)

Important Questions on Some Basic Concepts of Chemistry

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

Chlorine has two naturally occurring isotopes.

^{35} C l

and

^{37} C l

. If the atomic mass if

C l

is 35.45, the ratio of natural abundance of

^{35} C l

and

^{37} C l

is closest to

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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

HARD

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

Natural abundances of

^{12} C

and

^{13} C

isotopes of carbon are

99 %

and

1 %

respectively. Assuming they only contributes to the molecular weight of

C_{2} F_{4}

, the percentage of

C_{2} F_{4}

having a molecular mass of

101

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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

Calculate:

Mass of 5 gram atoms of calcium.
[Hint: Gram atoms mass: $Ca = 40 g$ ]

EASY

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

The common isotopes of carbon are

{}^{12}C

and

{}^{13}C

. The average mass of carbon is

12.01115 amu

. What is the abundance of the

{}^{13}C

isotope?

EASY

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

Which symbol replaced the unit of atomic mass, amu?

EASY

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

What will be the mass of one atom of

{}^{12}C

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

Calculate:

How many gram atoms of sodium is present in $115 g$ sodium?

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 :

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

If we consider

1 / 6

, in place of

1 / 12

of mass of carbon atom as relative atomic mass unit, the mass of one mole of substance will

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

A sample of copper sulphate pentahydrate contains

8.64

g of oxygen. How many gram of Cu is present in this sample?

(Atomic mass of Cu =

63.6

, S =

32.06

, O =

16

)

EASY

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

The average atomic mass of a mixture containing

79 m o l e %

{}^{24}{M g}

remaining

21 m o l e %

{}^{25}{M g}

and

{}^{26}{M g}

24.31 %

. Mole of

{}^{26}{M g}

is -

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

Which of the following has smallest mass?

EASY

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

Number of atoms of He in

100

u of He (atomic weight of He is

4

) are

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

Boron has two stable isotopes.

^{10} B (19 %) and^{11} B (81 %) .

Average atomic weight for boron in the periodic table is

EASY

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

Number of atoms of He in 100 u of He (atomic weight of He is 4) are

EASY

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

Define: gram-atomic mas.

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

8

g of a radioactive isotope has a half-life of

10

hrs, then the half-life of

2

g of the same substance is

An element 'A' have 3 isotopes A²⁴,A²⁸ & A³⁰,if percentage abundance of A²⁴ is 50% then calculate percentage abundance of A²⁸ and A³⁰ (Given : average atomic mass = 26.8)

Important Questions on Some Basic Concepts of Chemistry

Learn and Prepare for any exam you want !

An element 'A' have 3 isotopes A²⁴,A²⁸ & A³⁰,if percentage abundance of A²⁴ is 50% then calculate percentage abundance of A²⁸ and A³⁰
(Given : average atomic mass = 26.8)