Chemistry: Calculate the percentage of water for each of the hydrates listed: a. MgSO4 ● 7H2O b. LiC2H3O2 ● 2H2O c. Al(NO3)3 ● 9H2O

YOURE IN THE WRONG APP MY GUY...

Calculate the percentage of water for each of

Ответ:

saifulcrc468

17.04.2021

Chemistry

Mass ratio:

a. Approximately $51.2\%$ .

b. Approximately $35.3\%$ .

c. Approximately $43.2\%$ .

Explanation:

Look up the relative atomic mass of each element on a modern periodic table:

$\rm Mg$ : 24.305

. $\rm S$ : 32.06

. $\rm O$ : 15.999

. $\rm H$ : 1.008

. $\rm Li$ : 6.94

. $\rm C$ : 12.011

. $\rm Al$ : 26.982

. $\rm N$ : 14.007

For example, the relative atomic mass of $\rm Al$ is 26.982 . Hence, the mass of one mole of $\rm Al\!$ atoms would be (approximately) $26.982\; \rm g$ .

Calculate the formula mass of $\rm H_2O$ :

$\begin{aligned} & M({\rm H_2O}) \\ &= 2 \times 1.008 + 15.999 \\ &= 18.015\; \rm g \cdot mol^{-1}\end{aligned}$ .

Calculate the formula mass for each of the hydrates:

$\begin{aligned}& M({\rm MgSO_4 \cdot {7\, H_2O}}) \\ &= 24.305 + 32.06 + 4 \times 15.999 \\ & \quad\quad + 7 \times (2 \times 1.008 + 15.999) \\ &= 246.466\; \rm g \cdot mol^{-1}\end{aligned}$ .

$\begin{aligned}& M({\rm LiC_2H_3O_2 \cdot {2\, H_2O}}) \\ &= 6.94 + 2 \times 12.011 + 3 \times 1.008 + 2 \times 15.999 \\ & \quad\quad + 2 \times (2 \times 1.008 + 15.999) \\ &= 102.014\; \rm g \cdot mol^{-1}\end{aligned}$ .

$\begin{aligned}& M({\rm Al(NO_3)_3 \cdot {9\, H_2O}}) \\ &= 26.982 + 3 \times (14.007 + 3 \time 15.999) \\ &\quad \quad + 9 \times (2 \times 1.008 + 15.999) \\ &= 375.129\; \rm g \cdot mol^{-1}\end{aligned}$ .

The mass of $1\; \rm mol$ of ${\rm MgSO_4 \cdot {7\, H_2O}}$ formula units is $246.466\; \rm g$ .

There are seven mole of $\rm H_2O$ formula units in that many ${\rm MgSO_4 \cdot {7\, H_2O}}$ formula units. The mass of that $7\; \rm mol$ of $\rm H_2O\!$ formula units would be $7 \; \rm mol \times 18.015\; \rm g \cdot mol^{-1} = 127.105\; \rm g$ .

Hence, the percentage mass of $\rm H_2O$ in ${\rm MgSO_4 \cdot {7\, H_2O}}$ would be:

$\begin{aligned}\frac{127.015\; \rm g}{246.466\; \rm g} \approx 51.2\%\end{aligned}$ .

Similarly:

Mass of $1\;\rm mol$ of $\rm LiC_2H_3O_2 \cdot {2\, H_2O}$ formula units: $102.014\; \rm g$ .Mass of the $2\; \rm mol$ of $\rm H_2O$ in that $1\;\rm mol$ of $\rm LiC_2H_3O_2 \cdot {2\, H_2O}$ formula units: $2 \; \rm mol \times 18.015\; \rm g \cdot mol^{-1} = 36.030\; \rm g$ .Percentage mass of $\rm H_2O$ in $\rm LiC_2H_3O_2 \cdot {2\, H_2O}$ : $\begin{aligned}\frac{36.030\; \rm g}{102.014\; \rm g} \approx 35.3\%\end{aligned}$ .Mass of $1\;\rm mol$ of $\rm Al(NO_3)_3 \cdot {9\, H_2O}$ formula units: $375.129\; \rm g$ .Mass of the $9\; \rm mol$ of $\rm H_2O$ in that $1\;\rm mol$ of $\rm Al(NO_3)_3 \cdot {9\, H_2O}$ formula units: $9 \; \rm mol \times 18.015\; \rm g \cdot mol^{-1} = 162.135\; \rm g$ .Percentage mass of $\rm H_2O$ in $\rm Al(NO_3)_3 \cdot {9\, H_2O}$ : $\begin{aligned}\frac{162.135\; \rm g}{375.129\; \rm g} \approx 43.2\%\end{aligned}$ .

0,0(0 оценок)

Calculate the percentage of water for each of the hydrates listed: a. MgSO4 ● 7H2O

b. LiC2H3O2 ● 2H2O

c. Al(NO3)3 ● 9H2O

Ответ:

Ответ:

Ask your question to the AI advisor

More tips

Answers on questions: Chemistry

Ask an AI advisor a question