Chapter 2, Problem 123QRT

(a)

Interpretation Introduction

Interpretation:

In the pair of $\text{1}\text{mol}$ $\text{Cl}$ or $\text{1}\text{mol}$ ${\text{Cl}}_{\text{2}}$, the one which have greater number of atoms has to be given.

Explanation of Solution

Sample containing $\text{1}\text{mol}$ ${\text{Cl}}_{\text{2}}$ has more atoms than a sample containing $\text{1}\text{mol}$ $\text{Cl}$, since the molecule of ${\text{Cl}}_{\text{2}}$ contain two atoms of $\text{Cl}$.

(b)

Interpretation Introduction

Interpretation:

In the pair of 1 molecule ${\text{O}}_{\text{2}}$ or $\text{1}\text{mol}$ ${\text{O}}_{\text{2}}$, the one which have greater number of atoms has to be given.

Explanation of Solution

Sample containing $\text{1}\text{mol}$ of ${\text{O}}_{\text{2}}$ contains $\text{6}\text{.022}\text{×}{\text{10}}^{\text{23}}$ molecules of ${\text{O}}_{\text{2}}$.  This will contain more atoms than a sample containing 1 molecule ${\text{O}}_{\text{2}}$.

(c)

Interpretation Introduction

Interpretation:

In the pair of 1 nitrogen atom or 1 nitrogen molecule the one which have greater number of atoms has to be given.

Explanation of Solution

Sample containing 1 nitrogen molecule (${\text{N}}_{\text{2}}$) has two atoms, which is more than one nitrogen atom.

(d)

Interpretation Introduction

Interpretation:

In the pair of $\text{1}\text{mol}$ fluorine or $\text{6}\text{.032}\text{×}{\text{10}}^{\text{23}}$ fluorine molecule the one which have greater number of atoms has to be given.

Explanation of Solution

Sample containing $\text{6}\text{.032}\text{×}{\text{10}}^{\text{23}}$ fluorine molecules have more than $\text{1}\text{mol}$ of ${\text{F}}_{\text{2}}$ molecules, which has only $\text{6}\text{.032}\text{×}{\text{10}}^{\text{23}}$ molecules of ${\text{F}}_{\text{2}}$.

(e)

Interpretation Introduction

Interpretation:

In the pair of $\text{20}\text{.3}\text{g}$ $\text{Ne}$ or $\text{1}\text{mol}\text{Ne}$ the one which have greater number of atoms has to be given.

Explanation of Solution

The molar mass of $\text{Ne}$ is $\text{20}\text{.18}\text{g/mol}$, therefore a sample of $\text{20}\text{.3}\text{g}$ $\text{Ne}$ contains more than $\text{1}\text{mol}\text{Ne}$.

(f)

Interpretation Introduction

Interpretation:

In the pair of $\text{1}\text{molecule}{\text{Br}}_{\text{2}}$ or $\text{159}\text{.8g}{\text{Br}}_{\text{2}}$ the one which have greater number of atoms has to be given.

Explanation of Solution

The molar mass of bromine is $79.9\text{g/mol}$.  For ${\text{Br}}_{\text{2}}$ the mass will be $\text{159}\text{.8}\text{g/mol}{\text{Br}}_{\text{2}}$, so the sample composed of $\text{159}\text{.8g}$ bromine contains $\text{1}\text{mol}$ bromine which equals $\text{6}\text{.022}\text{×}{\text{10}}^{\text{23}}$ molecules.  This $\text{159}\text{.8g}$ sample has more particles than a sample containing $\text{1}\text{molecule}{\text{Br}}_{\text{2}}$.

(g)

Interpretation Introduction

Interpretation:

In the pair of $\text{107}\text{.9}\text{g}\text{Ag}\text{or}\text{9}\text{.6}\text{g}\text{Li}$ the one which have greater number of atoms has to be given.

Explanation of Solution

The molar mass of silver is $107.9\text{g/mol}$, so a sample of $\text{107}\text{.9}\text{g}\text{Ag}$ contains $\text{1}\text{mol}\text{Ag}$.  The molar mass of lithium is $6.9\text{g/mol}$, so a sample of $\text{9}\text{.6}\text{g}\text{Li}$ contains more than $\text{1}\text{mol}\text{of}\text{Li}$.

(h)

Interpretation Introduction

Interpretation:

In the pair of $\text{58}\text{.9}\text{g}\text{Co}\text{or}\text{58}\text{.9}\text{g}\text{Cu}$ the one which have greater number of atoms has to be given.

Explanation of Solution

The molar mass of $\text{Co}$ is $\text{58}\text{.9}\text{g/mol}$, so the sample with $\text{58}\text{.9}\text{g}$ of cobalt contains $\text{1}\text{mol}\text{Co}$ atoms.  The molar mass of copper is $\text{63}\text{.55}\text{g/mol}$, so the sample with $\text{58}\text{.9}\text{g}$ of copper contains less than $\text{1}\text{mol}\text{of}$ copper atoms.  Therefore the cobalt has more atoms than copper.

(i)

Interpretation Introduction

Interpretation:

In the pair of $1\text{g}\text{Ca}\text{or}6.022\times {10}^{23}$ calcium atoms the one which have greater number of atoms has to be given.

Explanation of Solution

The sample containing $\text{6}{\text{.022×10}}^{\text{23}}$ atoms of calcium contains $\text{1}\text{mol}$ of calcium atoms.  The molar mass of calcium is $\text{40}\text{.1}\text{g/mol}$, so the sample composed of calcium contains less than $\text{1}\text{mol}$ of calcium.  Thus the sample with $\text{6}{\text{.022×10}}^{\text{23}}$ calcium atoms has more particles than a sample with one gram calcium.

(j)

Interpretation Introduction

Interpretation:

In the pair of $\text{1}\text{g}\text{Cl}\text{atoms}\text{or}\text{1}\text{g}\text{Cl}\text{molecules}$, the one which have greater number of atoms has to be given.

Explanation of Solution

Since chlorine atoms all weigh the same, so two samples with identical mass containing chlorine must have the same number of chlorine atoms.  The molar mass of ${\text{Cl}}_{\text{2}}$ is twice that of $\text{Cl}$, but the number of molecule is half the number of atoms, if the samples are both $\text{1}\text{g}$.