Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 95

HARD

11th CBSE

IMPORTANT

Earn 100

The prefix 'giga' represents $10^{X}$ , where $X$ is

50% studentsanswered this correctly

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 96

The number of significant figures in the value

0.000524000

is

HARD

11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 97

Copper reacts with nitric acid to form copper (

II

) nitrate, nitric oxide and water. The number of nitric acid molecules in the balanced equation is

HARD

11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 98

Silver (atomic weight =

108 g {mol}^{- 1}

) has a density of

10.5 g {cm}^{- 3}

. The number of silver atoms on a surface of area

10^{- 12} m^{2}

can be expressed in scientific notation as

y \times 10^{x}

. The value of x is

EASY

11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 99

Among the following, the number of elements showing only one non-zero oxidation state is

$O, Cl, F, N, P, Sn, Tl, Na, Ti$ .

HARD

11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 100

The value of

n

in the molecular formula

{Be}_{n} {Al}_{2} {Si}_{6} O_{18}

.

MEDIUM

11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 101

A student performs a titration with different burettes and finds titre values of

25.2 mL, 25.25 mL

, and

25.0 mL

. The number of significant figures in the average titre value is

HARD

11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 102

Reaction of

{Br}_{2}

with

{Na}_{2} {CO}_{3}

in aqueous solution gives sodium bromide and sodium bromate with evolution of

{CO}_{2}

gas. The number of sodium bromide molecules involved in the balanced chemical equation is

HARD

11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 1 - Some Basic Concepts of Chemistry>Competition Focus>Q 103

If the value of Avogadro's number is

6.023 x 10^{23} {mol}^{- 1}

and the value of Boltzmann constant is

1.380 x 10^{- 23} {JK}^{- 1}

, then the number of significant figures in the calculated value of the universal gas constant is