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

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11th CBSE

IMPORTANT

Earn 100

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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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 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

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11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 42

The ratio of mass percent of

C

and

H

of a organic compound

(C_{x} H_{y} O_{z})

is

6 : 1

. If one molecule of the above compound

(C_{x} H_{y} O_{z})

contains half as much oxygen as required to burn one molecule of compound

C_{x} H_{y}

completely to

{CO}_{2}

and

H_{2} O

, the empirical formula of the compound

(C_{x} H_{y} O_{z})

is

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11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 43

In Haber's process,

30

litres of dihydrogen and

30

litres of dinitrogen were taken for reaction which yielded only

50 %

of the expected product. What will be the composition of the gaseous mixture under the aforesaid condition in the end ?