Question

determine the percentage composition of each of the compounds below

1. $kmno_4$

$k = \frac{39.1}{}$
$mn = \frac{54.9}{}$
$o = \frac{16.0}{}$

1. $hcl$

$h = $
$cl = $

1. $mg(no_3)_2$

$mg = $
$n = $
$o = $

1. $(nh_4)_3po_4$

$n = $
$h = $
$p = $
$o = $

1. $al_2(so_4)_3$

$al = $
$s = $
$o = $

solve the following problems

1. how many grams of oxygen can be produced from the decomposition of 100. g
2. how much can be produced from 20.0 g of $h_2o_2$
3. how much silver can be produced from 125 g of $ag_2o$

Explanation:

1. For $\text{KMnO}_4$

Step1: Calculate molar mass

Molar mass of $\text{KMnO}_4$ = $39.1 + 54.9 + 4\times16.0 = 158.0\ \text{g/mol}$

Step2: Find % of K

$\% \text{K} = \frac{39.1}{158.0} \times 100 = 24.7\%$

Step3: Find % of Mn

$\% \text{Mn} = \frac{54.9}{158.0} \times 100 = 34.8\%$

Step4: Find % of O

$\% \text{O} = \frac{64.0}{158.0} \times 100 = 40.5\%$

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2. For $\text{HCl}$

Step1: Calculate molar mass

Molar mass of $\text{HCl}$ = $1.0 + 35.5 = 36.5\ \text{g/mol}$

Step2: Find % of H

$\% \text{H} = \frac{1.0}{36.5} \times 100 = 2.7\%$

Step3: Find % of Cl

$\% \text{Cl} = \frac{35.5}{36.5} \times 100 = 97.3\%$

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3. For $\text{Mg(NO}_3\text{)}_2$

Step1: Calculate molar mass

Molar mass of $\text{Mg(NO}_3\text{)}_2$ = $24.3 + 2\times(14.0 + 3\times16.0) = 148.3\ \text{g/mol}$

Step2: Find % of Mg

$\% \text{Mg} = \frac{24.3}{148.3} \times 100 = 16.4\%$

Step3: Find % of N

$\% \text{N} = \frac{2\times14.0}{148.3} \times 100 = 18.9\%$

Step4: Find % of O

$\% \text{O} = \frac{6\times16.0}{148.3} \times 100 = 64.7\%$

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4. For $\text{(NH}_4\text{)}_3\text{PO}_4$

Step1: Calculate molar mass

Molar mass of $\text{(NH}_4\text{)}_3\text{PO}_4$ = $3\times(14.0+4\times1.0) + 31.0 + 4\times16.0 = 149.0\ \text{g/mol}$

Step2: Find % of N

$\% \text{N} = \frac{3\times14.0}{149.0} \times 100 = 28.2\%$

Step3: Find % of H

$\% \text{H} = \frac{12\times1.0}{149.0} \times 100 = 8.1\%$

Step4: Find % of P

$\% \text{P} = \frac{31.0}{149.0} \times 100 = 20.8\%$

Step5: Find % of O

$\% \text{O} = \frac{4\times16.0}{149.0} \times 100 = 43.0\%$

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5. For $\text{Al}_2\text{(SO}_4\text{)}_3$

Step1: Calculate molar mass

Molar mass of $\text{Al}_2\text{(SO}_4\text{)}_3$ = $2\times27.0 + 3\times(32.1 + 4\times16.0) = 342.3\ \text{g/mol}$

Step2: Find % of Al

$\% \text{Al} = \frac{2\times27.0}{342.3} \times 100 = 15.8\%$

Step3: Find % of S

$\% \text{S} = \frac{3\times32.1}{342.3} \times 100 = 28.1\%$

Step4: Find % of O

$\% \text{O} = \frac{12\times16.0}{342.3} \times 100 = 56.1\%$

Answer:

1. $\text{KMnO}_4$:

$\text{K} = 24.7\%$, $\text{Mn} = 34.8\%$, $\text{O} = 40.5\%$

1. $\text{HCl}$:

$\text{H} = 2.7\%$, $\text{Cl} = 97.3\%$

1. $\text{Mg(NO}_3\text{)}_2$:

$\text{Mg} = 16.4\%$, $\text{N} = 18.9\%$, $\text{O} = 64.7\%$

1. $\text{(NH}_4\text{)}_3\text{PO}_4$:

$\text{N} = 28.2\%$, $\text{H} = 8.1\%$, $\text{P} = 20.8\%$, $\text{O} = 43.0\%$

1. $\text{Al}_2\text{(SO}_4\text{)}_3$:

$\text{Al} = 15.8\%$, $\text{S} = 28.1\%$, $\text{O} = 56.1\%$