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An element, X has the following isotopic composition

$^{200} X : 90%$ $^{199} X : 8.0 %$ $^{202} X : 2.0 %$

The weighted average atomic mass of the naturally occurring element X is closest to

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Important Questions on Some Basic Concepts of Chemistry

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?

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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:

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

One mole of dioxygen gas at

STP

is equal to

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

Which symbol replaced the unit of atomic mass, amu?

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

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

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 :

MEDIUM

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

EASY

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

3.011 \times 10^{22}

atoms of an element weigh

1.15 gm

. The atomic mass of the element is.

EASY

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

If we consider that

\frac{1}{6},

in place of

\frac{1}{12}

, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

EASY

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

If molecular mass and atomic mass of sulphur are

256

and

32

respectively, its atomicity is

EASY

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

Number of protons, neutrons and electrons in the element

_{89}^{231} Y

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

Number of atoms of oxygen present in 10.6 g of

{N a}_{2} {C O}_{3}

will be

EASY

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

The nucleus of the element

_{21} E^{45}

contains

EASY

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

The molecular weight of air will be

(the components of air given as

N_{2} - 78 %, O_{2} - 21 %, Ar - 0.9 %

and

{CO}_{2} - 0 .1 %)

An element, X has the following isotopic composition 200X:90% 199X:8.0% 202X:2.0% The weighted average atomic mass of the naturally occurring element X is closest to

Important Questions on Some Basic Concepts of Chemistry

Learn and Prepare for any exam you want !

An element, X has the following isotopic composition

$^{200} X : 90%$ $^{199} X : 8.0 %$ $^{202} X : 2.0 %$

The weighted average atomic mass of the naturally occurring element X is closest to