Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 33

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11th CBSE

IMPORTANT

Earn 100

The ratio of masses of oxygen and nitrogen in a particular gaseous mixture is $1 : 4$ . The ratio of the number of their molecules is

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Important Questions on Some Basic Concepts of Chemistry

HARD

11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 34

A mixture of gases contains

H_{2}

and

O_{2}

gases in the ratio of

1 : 4 (w / w)

. What is the molar ratio of two gases in the mixture?

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11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 35

Suppose two elements

X

and

Y

combines to form two compounds

{XY}_{2}

and

X_{3} Y_{2}

. When

0.1 mol

of

{XY}_{2}

weighs

10 g

and

0.05 mol

of

X_{3} Y_{2}

weighs

9 g

, the atomic weights of

X

and

Y

are

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11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 36

An organic compound made of

C

,

H

and

N

contains

20 %

nitrogen. It's minimum molecular weight is

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11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 37

The percentage of

Se

in peroxidase anhydrous enzyme is

0.5 %

by weight (atomic weight

= 78.4

). Then minimum molecular weight of peroxidase anhydrous enzyme is

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11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 38

An alkaloid contains

17.28 %

of nitrogen and its molecular mass is

162

. The number of nitrogen atoms present in one molecule of the alkaloid is

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11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 39

The crystalline salt

{Na}_{2} {SO}_{4}

on heating loses

55.9 %

of its weight. The formula of the crystalline salt is loses

55.9 %

of its weight. The formula of the crystalline salt is

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11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 40

0.1 mole

of a carbohydrate with empirical formula

{CH}_{2} O

contains

1 g

of hydrogen. What is its molecular formula ?

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11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 41

The most abundant elements by mass in the body of a healthy human adult are: Oxygen (

61.4 %

), Carbon (

22.9 %

), Hydrogen (

10.0 %

) and Nitrogen (

2.6 %

). The weight which a

75 kg

person would gain if all the

1 H

atoms are replaced by

2 H

atoms is