How many grams of O₂ can be prepared from the thermal decomposition of 4.27 kg of HgO? Name and calculate the mass (in kg) of the other product.

Thermal decomposition of HgO forms Hg and O₂. The balanced equation is

According to the question,

Mass of HgO = 4.27kg = 4270g

Molecular mass of HgO = 216.6g/mol

Again you know,

$\mathit{m}\mathit{o}\mathit{l}\mathit{e}\mathit{s}\mathbf{=}\frac{\mathbf{m}\mathbf{a}\mathbf{s}\mathbf{s}\mathbf{\left(}\mathbf{g}\mathbf{i}\mathbf{v}\mathbf{e}\mathbf{n}\mathbf{\right)}}{\mathbf{m}\mathbf{a}\mathbf{s}\mathbf{s}\mathbf{\left(}\mathbf{m}\mathbf{o}\mathbf{l}\mathbf{a}\mathbf{r}\mathbf{\right)}}$

Moles of HgO

$\begin{array}{l}\mathbf{=}\frac{\mathbf{4270}}{\mathbf{216}\mathbf{.6}}\mathbf{\left(}\mathbf{m}\mathbf{o}\mathbf{l}\mathbf{\right)}\\ \mathbf{=}\mathbf{19}\mathbf{.7137}\mathbf{\left(}\mathbf{m}\mathbf{o}\mathbf{l}\mathbf{\right)}\end{array}$

Hence, moles of HgO are 19.7137mol.

According to the balanced equation

$\mathbf{2}\mathit{H}\mathit{g}\mathit{O}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\stackrel{\mathbf{\Delta }}{\mathbf{\to }}\mathbf{2}\mathit{H}\mathit{g}\mathbf{\left(}\mathbf{l}\mathbf{\right)}\mathbf{+}{\mathit{O}}_{\mathbf{2}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}$

2 moles of HgO produces 1 mole O₂

$\begin{array}{l}\mathbf{=}\mathbf{19}\mathbf{.7137}\mathbf{\times }\frac{\mathbf{1}}{\mathbf{2}}\mathbf{\left(}\mathbf{m}\mathbf{o}\mathbf{l}\mathbf{\right)}\\ \mathbf{=}\mathbf{9}\mathbf{.85685}\mathbf{\left(}\mathbf{m}\mathbf{o}\mathbf{l}\mathbf{\right)}\end{array}$

Now, moles of O₂

Hence, moles of O₂ are 9.85685mol.

Again you know,

$\mathit{m}\mathit{a}\mathit{s}\mathit{s}\mathbf{=}\mathit{m}\mathit{o}\mathit{l}\mathit{e}\mathit{s}\mathbf{\times }\mathit{m}\mathit{a}\mathit{s}\mathit{s}\mathbf{\left(}\mathbf{m}\mathbf{o}\mathbf{l}\mathbf{a}\mathbf{r}\mathbf{\right)}$

Molar mass of O₂ is 32g/mol.

Now, mass of O₂

$\begin{array}{l}\mathbf{=}\mathbf{9}\mathbf{.85685}\mathbf{\times }\mathbf{32}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\\ \mathbf{=}\mathbf{315}\mathbf{.4192}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\end{array}$

Hence, 315.4192g of O₂ can be prepared from the thermal decomposition of 4.27 kg of HgO.

According to the balanced equation

$\mathbf{2}\mathit{H}\mathit{g}\mathit{O}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\stackrel{\mathbf{\Delta }}{\mathbf{\to }}\mathbf{2}\mathit{H}\mathit{g}\mathbf{\left(}\mathbf{l}\mathbf{\right)}\mathbf{+}{\mathit{O}}_{\mathbf{2}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}$

2 moles of HgO produces 2 moles of Hg.

Now, moles of Hg

$\begin{array}{l}\mathbf{=}\mathbf{19}\mathbf{.7137}\mathbf{\times }\frac{\mathbf{2}}{\mathbf{2}}\mathbf{\left(}\mathbf{m}\mathbf{o}\mathbf{l}\mathbf{\right)}\\ \mathbf{=}\mathbf{19}\mathbf{.7137}\mathbf{\left(}\mathbf{m}\mathbf{o}\mathbf{l}\mathbf{\right)}\end{array}$

Hence, moles of Hg are 19.7137mol.

Again you know,

$\mathit{m}\mathit{a}\mathit{s}\mathit{s}\mathbf{=}\mathit{m}\mathit{o}\mathit{l}\mathit{e}\mathit{s}\mathbf{\times }\mathit{m}\mathit{a}\mathit{s}\mathit{s}\mathbf{\left(}\mathbf{m}\mathbf{o}\mathbf{l}\mathbf{a}\mathbf{r}\mathbf{\right)}$

Molar mass of Hg is 200.6g/mol.

Now, mass of Hg

data-custom-editor="chemistry" $\begin{array}{l}\mathbf{=}\mathbf{19}\mathbf{.7137}\mathbf{\times }\mathbf{200}\mathbf{.6}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\\ \mathbf{=}\mathbf{3954}\mathbf{.568}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\\ \mathbf{=}\mathbf{3}\mathbf{.95}\mathbf{\left(}\mathbf{k}\mathbf{g}\mathbf{\right)}\end{array}$

Hence, the other product is Hg.

3.95kg of Hg can be prepared from the thermal decomposition of 4.27 kg of HgO.