Answer:
0.004522 moles of hydrogen peroxide molecules are present.
Explanation:
Mass by mass percentage of hydrogen peroxide solution = w/w% = 3%
Mass of the solution , m= 5.125 g
Mass of the hydrogen peroxide = x
[tex]w/w\% = \frac{x}{m}\times 100[/tex]
[tex]3\%=\frac{x}{5.125 g}\times 100[/tex]
[tex]x=\frac{3\times 5.125 g}{100}=0.15375 g[/tex]
Mass of hydregn pervade in the solution = 0.15375 g
Moles of hydregn pervade in the solution :
[tex]=\fraC{ 0.15375 g}{34 g/mol}=0.004522 mol[/tex]
0.004522 moles of hydrogen peroxide molecules are present.
There are 0.0045 moles of H2O2 present.
For percent (mass/mass)concentration, we use the following formula;
% = mass of solute/ mass of solute + mass of solution × 100/1
mass of solution = 5.125 g
Mass of solute = x
Substituting values;
3 = x/x + (5.125 - x) × 100/1
Mass of solvent = mass of solution - mass of solute = 5.125 - x
3(5.125) = 100x
x = 0.154 g
Recall that number of moles = mass/molar mass
Molar mass of H2O2 = 34 g/mol
Number of moles of H2O2 = 0.154 g/34 g/mol = 0.0045 moles
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