Question

How many grams of aluminum sulfate must be dissolved in 650. mL of water to make 84.0% (m/v) aluminum sulfate solution?

Answer 1

3415.2 grams

Step-by-step explanation

to solve this we can use a rule of three

Step 1

Let

water= 100-84%= 16%

so,

`\text{ 16 \%=650 mL}`

for the water , 1 mL = 1 gram , so

`\text{ 16\% =650 grams}`

now, let represents the mass of the aluminiu, so

`\text{ 84 \%= x}`

a) the ratio is the same, so we have a proportion

`(16)/(650)=(84)/(x)`

Step 2

finally, solve for x

`\begin{gathered} (16)/(650)=(84)/(x) \\ \text{cross multiply } \\ 16\cdot x=84\cdot650 \\ 16x=54600 \\ \text{divide both sides by 16} \\ (16x)/(16)=(54600)/(16) \\ x=3412.5 \end{gathered}`

so, the mass of the aluminum is

3415.2 grams