If Avogadro number N A , is changed from 6.022 × 10 23 m o l - 1 to 6.022 × 10 20 m o l - 1 , this would change:

The definition of mass in units of grams

The ratio of chemical species to each other in a balanced equation.

The ratio of elements to each other in a compound.

5 moles of A B 2 weigh 125 × 10 - 3 k g and 10 moles of A 2 B 2 weigh 300 × 10 - 3 k g . The molar mass of A ( M A ) and molar mass of B ( M B ) in k g m o l - 1 are:

M A = 5 × 10 - 3 and M B = 10 × 10 - 3

M A = 25 × 10 - 3 and M B = 50 × 10 - 3

M A = 50 × 10 - 3 and M B = 25 × 10 - 3

M A = 10 × 10 - 3 and M B = 5 × 10 - 3

25 g of an unknown hydrocarbon upon burning produces 88 g of C O 2 and 9 g of H 2 O . This unknown hydrocarbon contains:

24 g of carbon and 1 g of hydrogen

18 g of carbon annd 7 g of hydrogen

22 g of carbon and 3 g of hydrogen

20 g carbon and 5 g of hydrogen

EASY

Earn 100

The amount of phosphorus present in $1.375 g$ of ${PCl}_{3}$ is

(Atomic weight of $P = 31$ , $Cl = 35.5$ )

50% studentsanswered this correctly

Important Questions on Some Basic Concepts of Chemistry

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept

An unknown chlorohydrocarbon has 3.55 % of chlorine. If each molecule of the hydrocarbon has one chlorine atom only; chlorine atoms present in 1 g of chlorohydrocarbon are :(Atomic wt. of

Cl = 35 .5 u;

Avogadro constant

= 6 .023 \times 10^{23} {mol}^{- 1}

)

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept

If Avogadro number

N_{A}

, is changed from

6.022 \times 10^{23} m o l^{- 1}

6.022 \times 10^{20} m o l^{- 1}

, this would change:

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept

Suppose the elements

X

and

Y

combine to form two compounds

X Y_{2}

and

X_{3} Y_{2}

. When

0.1 mole

X Y_{2}

weighs

10 g

and

0.05 mole

X_{3} Y_{2}

weighs

9 g

, the atomic weights of

X

and

Y

are

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept

The amount of oxygen in

3.6

moles of water is:

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept

For the following reaction, the mass of water produced from

445 g

C_{57} H_{110} O_{6}

is:

2 C_{57} H_{110} O_{6} (s) + 163 O_{2} (g) \to 114 {CO}_{2} (g) + 110 H_{2} O (l)

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept

An amount of

18 g

glucose corresponds to:

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept

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 the two gases in the mixture?

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept

Consider the following reactions:

NaCl + K_{2} {Cr}_{2} O_{7} + \underset{(Conc.)}{H_{2} {SO}_{4}} \to (A) +

side products

(A) + N a O H \to (B) +

side products

(B) + \underset{(dilute)}{H_{2} S O_{4}} + H_{2} O_{2} \to (C) +

side products
The sum of the total number of atoms in one molecule each of

(A), (B)

and

(C)

is ________

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept

When

22.4

litres of

H_{2} (g)

is mixed with

11.2

litres of

C l_{2} (g),

each at STP, the moles of

H C l (g)

formed is equal to

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept

The amount of sugar

(C_{12} H_{22} O_{11})

required to prepare

2 L

of its

0 .1 M

aqueous solution is:

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept

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

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept

The number of moles of hydrogen molecules required to produce

20

moles of ammonia through Haber’s process is:

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept

Ferrous sulphate heptahydrate is used to fortify foods with iron. The amount (in grams) of the salt required to achieve

10 p p m

of iron in

100 k g

of wheat is ____________. (Up to two decimal place)
Atomic weight:

F e = 55.85; S = 32.00; O = 16.00

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept

The volume of oxygen at STP required to burn 2.4 g of carbon completely is:

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept

5

moles of

A B_{2}

weigh

125 \times 10^{- 3} k g

and

10

moles of

A_{2} B_{2}

weigh

300 \times 10^{- 3} k g

. The molar mass of A

(M_{A})

and molar mass of

B (M_{B})

k g {m o l}^{- 1}

are:

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept

The first and second ionisation enthalpies of a metal are

496

and

4560 k J m o l^{- 1}

, respectively. How many moles of

H C l

and

H_{2} S O_{4},

respectively, will be needed to react completely with

1

mole of the metal hydroxide?

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept

The flocculation value of

H C l

for arsenic sulphide

s o l

30 m m o l L^{- 1}

. If

H_{2} S O_{4}

is used for the flocculation of arsenic sulphide, the amount, in grams, of

H_{2} S O_{4}

250 m l

required for the above purpose is ________. (Round off to two digits after decimal.)
(molecular mass of

H_{2} {S O}_{4} = 98 g / m o l

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept

The number of water molecules is maximum in

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept

25 g

of an unknown hydrocarbon upon burning produces

88 g

C O_{2}

and

9 g

H_{2} O .

This unknown hydrocarbon contains:

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept

1

gram of a carbonate

(M_{2} {CO}_{3})

on treatment with excess

HCl

produces

0.01186

moles of

{CO}_{2}

. The molar mass of

M_{2} {CO}_{3}

{gmol}^{- 1}

is:

The amount of phosphorus present in 1.375 g of PCl3 is (Atomic weight of P=31, Cl=35.5)

Important Questions on Some Basic Concepts of Chemistry

Learn and Prepare for any exam you want !

The amount of phosphorus present in $1.375 g$ of ${PCl}_{3}$ is

(Atomic weight of $P = 31$ , $Cl = 35.5$ )