Question

TIMED PLS HELP ASAP AND WILL GIVE BRAINLIST

Answer 1

Answer: The theoretical yield of alum is 12.09 g

Explanation:

Molarity is calculated by using the equation:

$\text{Molarity}=\frac{\text{Moles}}{\text{Volume}}$ ......(1)

We are given:  

Molarity of sulfuric acid = 9.9 M

Volume of solution = 8.3 mL = 0.0083 L (Conversion factor: 1 L = 1000 mL)

Putting values in equation 1, we get:

$\text{Moles of sulfuric acid}=(9.9mol/L\times 0.0083L)=0.08217mol$

The given chemical equation follows:

$2Al+2KOH+4H_2SO_4+22H_2O\rightarrow 3H_2+2KAl(SO_4)_2.12H_2O$

By the stoichiometry of the reaction:

4 moles of sulfuric acid produces 2 moles of alum

So, 0.08217 moles of sulfuric acid will produce = $\frac{2}{4}\times 0.08217=0.0411mol$ of alum

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ ......(2)

Molar mass of alum = 294.24 g/mol

Plugging values in equation 2:

$\text{Mass of alum}=(0.0411mol\times 294.24g/mol)=12.09g$

Hence, the theoretical yield of alum is 12.09 g