2h2O2 + 2H2O ---> 2H2O + O2

If 50cmcube , 2.0 mole/dmcube of hydrogen peroxide is decomposed and volume of oxygen gas collected. How much hydrogen peroxide is decomposed?

Huh? it was given.

moles hydrogen peroxide=2.0mol/dm^3 * 50ml * (1dm^3/1000ml)

To determine how much hydrogen peroxide is decomposed, we can start by calculating the moles of hydrogen peroxide decomposed using the given volume and molarity.

First, convert the given volume from cm^3 to dm^3:
50 cm^3 = 50/1000 dm^3 = 0.05 dm^3

Next, we can use the molarity to determine the number of moles of hydrogen peroxide:
Molarity = Moles/Volume

Rearranging the equation, we have:
Moles = Molarity x Volume

Given:
Molarity = 2.0 moles/dm^3
Volume = 0.05 dm^3

Substituting the values into the equation, we can calculate the moles of hydrogen peroxide decomposed:
Moles = 2.0 moles/dm^3 x 0.05 dm^3
Moles = 0.1 moles

Therefore, 0.1 moles of hydrogen peroxide is decomposed.