Chapter U4.9, Problem 6E

(a)

Interpretation Introduction

Interpretation:

The species with more number of atoms from 12 g H or 12 g C needs to be determined.

Concept Introduction :

Gram atomic mass of an element contains Avogadro number (N_A) of atoms which is $6.02\times {10}^{23}$ .

Answer to Problem 6E

12 g H contains more atoms as compared to 12 g C.

Explanation of Solution

Number of gram atom of H in 12 g is 12. So number of atoms in 12 g H is $12\times N_A$ .

Number of gram atom of C in 12 g is 1. So number of atoms in 12 g C is $1\times N_A$ .

So, 12 g H contains more atoms as compared to 12 g C.

(b)

Interpretation Introduction

Interpretation:

The species with more number of atoms from 27 g Al or 27 g Fe needs to be determined.

Concept Introduction :

Gram atomic mass of an element contains Avogadro number (N_A) of atoms which is $6.02\times {10}^{23}$ .

Answer to Problem 6E

27 g Al contains more atoms as compared to 27 g Fe.

Explanation of Solution

Number of gram atom of Al in 27 g is 1. So number of atoms in 27 g Al is $1\times N_A$ .

Number of gram atom of Fe in 27 g is $27/56=0.48$ . Here, 56 is molar mass of Fe. So number of atoms in 27 g Fe is $0.48\times N_A$ .

So 27 g Al contains more atoms as compared to 27 g Fe.

(c)

Interpretation Introduction

Interpretation:

Whether 40 g Ca or 40 g Na has more atoms needs to be determined.

Concept Introduction :

Gram atomic mass of an element contains Avogadro number (N_A) of atoms which is $6.02\times {10}^{23}$ .

Answer to Problem 6E

40 g Na contains more atoms as compared to 40 g Ca.

Explanation of Solution

Number of gram atom of Na in 40 g is 40/23=1.74. So number of atoms in 40 g Na is $1.74\times N_A$ .

Number of gram atom of Ca in 40 g is 1. So number of atoms in 40 g Ca is $1\times N_A$ .

So, 40 g Na contains more atoms as compared to 40 g Ca.

(d)

Interpretation Introduction

Interpretation:

Whether 40 g Ca or 60 g Zn contain more atoms needs to be determined.

Concept Introduction :

Gram atomic mass of an element contains Avogadro number (N_A) of atoms which is

  $6.02\times {10}^{23}$ .

Answer to Problem 6E

40 g Ca contains more atoms as compared to 60 g Zn.

Explanation of Solution

Number of gm atom of Zn in 60 g is $60/65$ =0.92. Here, molar mass of Zn is 65 g/mol. So number of atoms in 60 g Zn is $0.92\times N_A$ .

Number of gram atom of Ca in 40 g is 1. So number of atoms in 40 g Ca is $1\times N_A$ .

So, 40 g Ca contains more atoms as compared to 60 g Zn.

(e)

Interpretation Introduction

Interpretation:

Whether 10 g Li or 100 g Pb contains more number of atoms needs to be determined.

Concept Introduction :

Gram atomic mass of an element contains Avogadro number (N_A) of atoms which is $6.02\times {10}^{23}$ .

Answer to Problem 6E

10 g Li contains more atoms as compared to 100 g Pb.

Explanation of Solution

Number of gram atom of Li in 10 g is $10/7=1.43$ . So number of atoms in 10 g Li is $1.43\times N_A$ .

Number of gram atom of Pb in 100 g is $100/207=0.48$ . So number of atoms in 100 g Pb is $0.48\times N_A$ .

So, 10 g Li contains more atoms as compared to 100 g Pb.