How many moles of H 2 O form when 25 . 0 mL of 0 . 10 MHNO 3 solution is completely neutralised by NaOH ?

Molarity = no . of moles of solute Volume of solution in L ...............(1) (as volume is given in ml we get no of moles in milli moles) Given that , Molarity of HNO 3 = 0 . 1 M Volume = 25 ml from (1) no of milli moles = ( Molarity ) × ( Volume in mL ) = ( 0 . 1 ) ( 25 ) = 2 . 5 milli moles The neutralisation reaction can be written as follows, HNO 3 + NaOH → NaNO 3 + H 2 O 1mole of nitric acid gives 1 mole of water Hence, the number milli moles of water produced from 2.5 milli moles of nitric acid =2.5 milli moles.

MEDIUM

JEE Main

IMPORTANT

Earn 100

Sulphur molecules exist under various conditions as $S_{8}, S_{6}, S_{4}, S_{2}$ and $S$ .

(a) Is the mass of one mole of each of these molecules the same?

(b) Is the number of molecules in one mole of each of these molecules the same?

(c) Is the mass of sulphur in one mole of each of these molecules the same?

(d) Is the number of atoms of sulphur in one mole of each of these molecules the same?

Important Questions on Elementary Problems Based on Definition of Mole: The Mole Concept

MEDIUM

JEE Main

IMPORTANT

Modern Approach to Chemical Calculations>Chapter 1 - Elementary Problems Based on Definition of Mole: The Mole Concept>PROBLEMS>Q 40

Two minerals that contain $Cu$ are ${CuFeS}_{2}$ and ${Cu}_{2} S$ . What mass in $lb$ of ${Cu}_{2} S$ would contain the same mass of $Cu$ as is contained in $125 lb$ of ${CuFeS}_{2}$ ?

Round off your answer to the nearest integer.

MEDIUM

JEE Main

IMPORTANT

Modern Approach to Chemical Calculations>Chapter 1 - Elementary Problems Based on Definition of Mole: The Mole Concept>PROBLEMS>Q 41

What is the maximum number of moles of

{CO}_{2}

that could be obtained from the carbon in

4 moles

{Ru}_{2} {({CO}_{3})}_{3} ?

MEDIUM

JEE Main

IMPORTANT

Modern Approach to Chemical Calculations>Chapter 1 - Elementary Problems Based on Definition of Mole: The Mole Concept>PROBLEMS>Q 42

What mass of

NaCl

would contain the same total number of ions as

245 g

{MgCl}_{2} ?

MEDIUM

JEE Main

IMPORTANT

Modern Approach to Chemical Calculations>Chapter 1 - Elementary Problems Based on Definition of Mole: The Mole Concept>PROBLEMS>Q 43

An unknown sample weighing

1.5 g

was found to contain only

Mn

and

S

. The sample was completely reacted with oxygen and it produced

1.22 g

Mn

oxide and

1.38 g

{SO}_{3} .

What is the simplest formula for this compound?

MEDIUM

JEE Main

IMPORTANT

Modern Approach to Chemical Calculations>Chapter 1 - Elementary Problems Based on Definition of Mole: The Mole Concept>PROBLEMS>Q 44

The two sources of

Zn,

i.e.,

{ZnSO}_{4}

and

Zn {({CH}_{3} COO)}_{2} \cdot 2 H_{2} O

, can be purchased at the same price per kilogram of the compound. Which is the most economical source of

Zn

and by how much?

MEDIUM

JEE Main

IMPORTANT

Modern Approach to Chemical Calculations>Chapter 1 - Elementary Problems Based on Definition of Mole: The Mole Concept>PROBLEMS>Q 45

How many moles of

H_{2} O

form when

25.0 mL

0.10 {MHNO}_{3}

solution is completely neutralised by

NaOH

EASY

JEE Main

IMPORTANT

Modern Approach to Chemical Calculations>Chapter 1 - Elementary Problems Based on Definition of Mole: The Mole Concept>PROBLEMS>Q 46

Which would be larger, an atomic mass unit based on the current standard or one based on the mass of a

Be - 9

atom set at exactly

9 amu ?

MEDIUM

JEE Main

IMPORTANT

Modern Approach to Chemical Calculations>Chapter 1 - Elementary Problems Based on Definition of Mole: The Mole Concept>PROBLEMS>Q 47

The enzyme carbonic anhydrase catalyses the hydration of

{CO}_{2}

. This reaction:

{CO}_{2} + H_{2} O \to H_{2} {CO}_{3}

is involved in the transfer of

{CO}_{2}

from tissues to the lungs via the bloodstream. One enzyme molecule hydrates

10^{6}

molecules of

{CO}_{2}

per second. How many kg of

{CO}_{2}

are hydrated in one hour in one litre by

1 \times 10^{- 6} M enzyme ?

Important Questions on Elementary Problems Based on Definition of Mole: The Mole Concept

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