Chapter 7, Problem 2PE

(a)

Interpretation Introduction

Interpretation:

The molar mass of $\text{NaOH}$ has to be given.

Answer to Problem 2PE

The molar mass of $\text{NaOH}$ is $\text{40}\text{g}\text{.}$

Explanation of Solution

Given,

The atomic mass of sodium atom $\text{=23}\text{g}$

The atomic mass of oxygen atom $\text{=16}\text{g}$

The atomic mass of Hydrogen atom $\text{=1}\text{g}$

The molecular formula can be calculated as,

Molecular formula of $\text{NaOH}$$\text{=23+1+16}$

Molecular formula of $\text{NaOH}$$\text{=40}\text{g}$

The molar mass of $\text{NaOH}$ is $\text{40}\text{g}\text{.}$

(b)

Interpretation Introduction

Interpretation:

The molar mass of ${\text{Ag}}_{\text{2}}{\text{CO}}_{\text{3}}$ has to be given.

Answer to Problem 2PE

The molar mass of ${\text{Ag}}_{\text{2}}{\text{CO}}_{\text{3}}$ is $276\text{g}\text{.}$

Explanation of Solution

Given,

The atomic mass of carbon atom $\text{=12}\text{g}$

The atomic mass of silver atom $\text{=108}\text{g}$

The atomic mass of oxygen atom $\text{=16}\text{g}$

The molecular formula can be calculated as,

Molecular formula of ${\text{Ag}}_{\text{2}}{\text{CO}}_{\text{3}}$$\text{=2×108+12+3×16}$

Molecular formula of ${\text{Ag}}_{\text{2}}{\text{CO}}_{\text{3}}$$\text{=276}\text{g}$

The molar mass of ${\text{Ag}}_{\text{2}}{\text{CO}}_{\text{3}}$ is $276\text{g}\text{.}$

(c)

Interpretation Introduction

Interpretation:

The molar mass of ${\text{Cr}}_{\text{2}}{\text{O}}_{\text{3}}$ has to be given.

Answer to Problem 2PE

The molar mass of ${\text{Cr}}_{\text{2}}{\text{O}}_{\text{3}}$ is $152\text{g}\text{.}$

Explanation of Solution

Given,

The atomic mass of chromium $\text{=52}\text{g}$

The atomic mass of oxygen atom $\text{=16}\text{g}$

The molecular formula can be calculated as,

Molecular formula of ${\text{Cr}}_{\text{2}}{\text{O}}_{\text{3}}$$\text{=2×52+3×16}$

Molecular formula of ${\text{Cr}}_{\text{2}}{\text{O}}_{\text{3}}$$\text{=152}\text{g}$

The molar mass of ${\text{Cr}}_{\text{2}}{\text{O}}_{\text{3}}$ is $152\text{g}\text{.}$

(d)

Interpretation Introduction

Interpretation:

The molar mass of ${\left({\text{NH}}_{\text{4}}\right)}_{\text{2}}{\text{CO}}_{\text{3}}$ has to be given.

Answer to Problem 2PE

The molar mass of ${\left({\text{NH}}_{\text{4}}\right)}_{\text{2}}{\text{CO}}_{\text{3}}$ is $96\text{g}\text{.}$

Explanation of Solution

Given,

The atomic mass of Nitrogen atom $\text{=14}\text{g}$

The atomic mass of carbon atom $\text{=12}\text{g}$

The atomic mass of Hydrogen atom $\text{=1}\text{g}$

The atomic mass of oxygen atom $\text{=16}\text{g}$

The molecular formula can be calculated as,

Molecular formula of ${\left({\text{NH}}_{\text{4}}\right)}_{\text{2}}{\text{CO}}_{\text{3}}$$\text{=2}\times \left(14+4\right)\text{+12+3}\times \text{16}$

Molecular formula of ${\left({\text{NH}}_{\text{4}}\right)}_{\text{2}}{\text{CO}}_{\text{3}}$$\text{=96}\text{g}$

The molar mass of ${\left({\text{NH}}_{\text{4}}\right)}_{\text{2}}{\text{CO}}_{\text{3}}$ is $96\text{g}\text{.}$

(e)

Interpretation Introduction

Interpretation:

The molar mass of $\text{Mg}{\left({\text{HCO}}_{\text{3}}\right)}_{\text{2}}$ has to be given.

Answer to Problem 2PE

The molar mass of $\text{Mg}{\left({\text{HCO}}_{\text{3}}\right)}_{\text{2}}$ is $146.3\text{g}\text{.}$

Explanation of Solution

Given,

The atomic mass of magnesium $\text{=24}\text{.3}\text{g}$

The atomic mass of carbon atom $\text{=12}\text{g}$

The atomic mass of Hydrogen atom $\text{=1}\text{g}$

The atomic mass of oxygen atom $\text{=16}\text{g}$

The molecular formula can be calculated as,

Molecular formula of $\text{Mg}{\left({\text{HCO}}_{\text{3}}\right)}_{\text{2}}$$\text{=24}\text{.3+2×}\left(\text{1+12+3×16}\right)$

Molecular formula of $\text{Mg}{\left({\text{HCO}}_{\text{3}}\right)}_{\text{2}}$$\text{=146}\text{.3}\text{g}$

The molar mass of $\text{Mg}{\left({\text{HCO}}_{\text{3}}\right)}_{\text{2}}$ is $146.3\text{g}\text{.}$

(f)

Interpretation Introduction

Interpretation:

The molar mass of ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{COOH}$ has to be given.

Answer to Problem 2PE

The molar mass of ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{COOH}$ is $122\text{g}\text{.}$

Explanation of Solution

Given,

The atomic mass of carbon atom $\text{=12}\text{g}$

The atomic mass of hydrogen atom $\text{=1}\text{g}$

The atomic mass of oxygen atom $\text{=16}\text{g}$

The molecular formula can be calculated as,

Molecular formula of ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{COOH}$$\text{=7×12+6+2×16}$

Molecular formula of ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{COOH}$$\text{=122}\text{g}$

The molar mass of ${\text{C}}_{\text{6}}{\text{H}}_{\text{5}}\text{COOH}$ is $122\text{g}\text{.}$

(g)

Interpretation Introduction

Interpretation:

The molar mass of ${\text{C}}_{\text{6}}{\text{H}}_{\text{12}}{\text{O}}_{\text{6}}$ has to be given.

Answer to Problem 2PE

The molar mass of ${\text{C}}_{\text{6}}{\text{H}}_{\text{12}}{\text{O}}_{\text{6}}$ is $180\text{g}\text{.}$

Explanation of Solution

Given,

The atomic mass of carbon atom $\text{=12}\text{g}$

The atomic mass of hydrogen atom $\text{=1}\text{g}$

The atomic mass of oxygen atom $\text{=16}\text{g}$

The molecular formula can be calculated as,

Molecular formula of ${\text{C}}_{\text{6}}{\text{H}}_{\text{12}}{\text{O}}_{\text{6}}$$\text{=6×12+12}\times \text{1+6×16}$

Molecular formula of ${\text{C}}_{\text{6}}{\text{H}}_{\text{12}}{\text{O}}_{\text{6}}$$\text{=180}\text{g}$

The molar mass of ${\text{C}}_{\text{6}}{\text{H}}_{\text{12}}{\text{O}}_{\text{6}}$ is $180\text{g}\text{.}$

(h)

Interpretation Introduction

Interpretation:

The molar mass of ${\text{K}}_{\text{4}}\text{Fe}{\left(\text{CN}\right)}_{\text{6}}$ has to be given.

Answer to Problem 2PE

The molar mass of ${\text{K}}_{\text{4}}\text{Fe}{\left(\text{CN}\right)}_{\text{6}}$ is $211.845\text{g}\text{.}$

Explanation of Solution

Given,

The atomic mass of potassium $\text{=39}\text{g}$

The atomic mass of iron atom $\text{=55}\text{.845}\text{g}$

The atomic mass of carbon atom $\text{=12}\text{g}$

The atomic mass of nitrogen atom $\text{=14}\text{g}$

The molecular formula can be calculated as,

Molecular formula of ${\text{K}}_{\text{4}}\text{Fe}{\left(\text{CN}\right)}_{\text{6}}$$\text{=4×39+55}\text{.845+}6\times \text{(12+14)}$

Molecular formula of ${\text{K}}_{\text{4}}\text{Fe}{\left(\text{CN}\right)}_{\text{6}}$$\text{=211}\text{.845}\text{g}$

The molar mass of ${\text{K}}_{\text{4}}\text{Fe}{\left(\text{CN}\right)}_{\text{6}}$ is $211.845\text{g}\text{.}$

(i)

Interpretation Introduction

Interpretation:

The molar mass of ${\text{BaCl}}_{\text{2}}{\text{.2H}}_{\text{2}}\text{O}$ has to be given.

Answer to Problem 2PE

The molar mass of ${\text{BaCl}}_{\text{2}}{\text{.2H}}_{\text{2}}\text{O}$ is $244.2\text{g}\text{.}$

Explanation of Solution

Given,

The atomic mass of barium atom $\text{=137}\text{.327}\text{g}$

The atomic mass of chlorine atom $\text{=35}\text{.45}\text{g}$

The atomic mass of oxygen atom $\text{=16}\text{g}$

The atomic mass of hydrogen atom $\text{=1}\text{g}$

The molecular formula can be calculated as,

Molecular formula of ${\text{BaCl}}_{\text{2}}{\text{.2H}}_{\text{2}}\text{O}$$\text{=137}\text{.327}\text{+2×35}\text{.45+2×}\left(\text{2+16}\right)$

Molecular formula of ${\text{BaCl}}_{\text{2}}{\text{.2H}}_{\text{2}}\text{O}$$\text{=244}\text{.2}\text{g}$

The molar mass of ${\text{BaCl}}_{\text{2}}{\text{.2H}}_{\text{2}}\text{O}$ is $244.2\text{g}\text{.}$