What mass of hyudrogen peroxide should result when 1.50 g of barium peroxide is reacted with 25.0 mL of 0.50 M of hydrochloric acid?

Here is a solved example of a stoichiometry problem. Just follow the steps. Remember M x L = moles.

http://www.jiskha.com/science/chemistry/stoichiometry.html

To determine the mass of hydrogen peroxide formed, we need to write and balance the chemical equation for the reaction between barium peroxide and hydrochloric acid.

The balanced equation is:
BaO2 + 2HCl -> BaCl2 + H2O2

According to the balanced equation, one mole of barium peroxide reacts with two moles of hydrochloric acid to produce one mole of hydrogen peroxide.

Now, let's calculate the number of moles of barium peroxide (BaO2) using its molar mass.

The molar mass of BaO2 is 169.336 g/mol (137.33 g/mol for Ba + 32.00 g/mol for O2).

1.50 g of BaO2 is equal to:
1.50 g / 169.336 g/mol = 0.008859 moles

Since the reaction is 1:1 between BaO2 and H2O2, we can conclude that 0.008859 moles of BaO2 will produce 0.008859 moles of H2O2.

Finally, to find the mass of hydrogen peroxide, we'll multiply the number of moles by its molar mass.

The molar mass of H2O2 is 34.0147 g/mol.

Mass of H2O2 = 0.008859 moles * 34.0147 g/mol = 0.296 g

Therefore, the mass of hydrogen peroxide formed is 0.296 grams.