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

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.

MEDIUM

Earn 100

The ratio of nitrogen and oxygen by mass percent in a colorless gas is $7 : 8$ . When this colourless gas combines with $O_{2}$ , it produces $44800 {cm}^{3}$ of a brown-coloured gas at STP. Find out the number of moles of oxygen that have taken part in the reaction.

Important Questions on Some Basic Concepts of Chemistry

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept and Molar Masses

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 and Molar Masses

The amount of oxygen in

3.6

moles of water is:

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept and Molar Masses

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 and Molar Masses

Which one of the following will have the largest number of atoms?

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept and Molar Masses

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 and Molar Masses

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?

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept and Molar Masses

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 and Molar Masses

Calculate the mass of

AgCl

precipitated, when

25 ml

35 %

solution of

{AgNO}_{3}

and

25 ml

11.6 %

solution of

NaCl

are mixed is

MEDIUM

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept and Molar Masses

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 and Molar Masses

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 and Molar Masses

0.023 \times 10^{22}

molecules are present in

10 g

of a substance

{}^{'}x^{'} .

The molarity of a solution containing

5 g

of substance 'x' in 2 L solution is

_________\times 10^{- 3}

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept and Molar Masses

The number of water molecules is maximum in

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept and Molar Masses

Which one of the followings has maximum number of atoms?

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept and Molar Masses

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 and Molar Masses

Which of the following has the largest number of moles?

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept and Molar Masses

How many moles of electrons will weigh one kilogram ?

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept and Molar Masses

Calculate the number of sulphate ions present in

100 ml

0.001 M H_{2} {SO}_{4} ?

EASY

Chemistry>Physical Chemistry>Some Basic Concepts of Chemistry>Mole Concept and Molar Masses

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 and Molar Masses

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 and Molar Masses

In which case the number of molecules of water maximum?

The ratio of nitrogen and oxygen by mass percent in a colorless gas is 7 : 8. When this colourless gas combines with O2, it produces 44800 cm3 of a brown-coloured gas at STP. Find out the number of moles of oxygen that have taken part in the reaction.

Important Questions on Some Basic Concepts of Chemistry

Learn and Prepare for any exam you want !

The ratio of nitrogen and oxygen by mass percent in a colorless gas is $7 : 8$ . When this colourless gas combines with $O_{2}$ , it produces $44800 {cm}^{3}$ of a brown-coloured gas at STP. Find out the number of moles of oxygen that have taken part in the reaction.