Question

What is the total volume of gas produced from the decomposition of `100cm^3` of `0.2 mol`/`dm^3` hydrogen peroxide(`H_2 O_2`)?

The balanced equation for the decomposition of `H_2 O_2` is: `H_2 O_2 -> 2H_2 O + O_2`

Answer 1

Approx. `250*mL`............

Explanation:

You have got the stoichiometric equation...

`2H_2O_2(aq) stackrel(MnO_2)rarr2H_2O(l) + O_2(g)uarr`

And this tells me UNEQUIVOCALLY that one mole of dioxygen gas results from the (usually Mn salt-catalyzed) decomposition of TWO mole of hydrogen peroxide. This is clearly a disproportionation reaction, in that peroxo `stackrel(-I)O` oxygen is reduced to water (`stackrel(-II)O`) and oxidized to dioxygen gas (`stackrel(0)O`)....

`"Moles of hydrogen peroxide="100*cm^3xx1xx10^-3*dm^3*cm^-3xx0.2*mol*dm^-3=0.020*mol`

And thus given complete reaction, `0.01*mol` of dioxygen gas is evolved.....

Under standard laboratory conditions, the molar volume of an ideal gas is `24.8*L*mol^-1` under the particular set of conditions specified (which may be different from your specification!)....

And so we take the product....`24.8*L*mol^-1xx0.010*mol-=??L`