Question

Hydrogen peroxide, H2O2H2O2, is used to disinfect contact lenses. 2H2O2(aq)→2H2O(l)+O2(g)2H2O2(aq)→2H2O(l)+O2(g) You may want to reference (Page) Section 6.1 while completing this problem.

Part A How many milliliters of O2(g)O2(g) at 27 ∘C∘C and 5.00 barrbarr can be liberated from 18.95 mLmL of an aqueous solution containing 3.00%% H2O2H2O2 by mass? The density of the aqueous solution of H2O2H2O2 is 1.01g/mLg/mL.

Answer 1

3% H2O2 by mass solution 3g of H2O2 present in 100g of solution

volume of solution = mass of solution/density

                          = 100/1.01   = 99ml

99ml of solution contains 3g of H2O2

18.95ml of solution contains = 3*18.95/99 = 0.574g

no of moles of H2O2 = W/G.M.Wt

                                = 0.574/34   = 0.0168moles

2H2O2(aq)→2H2O(l)+O2(g)

2 moles of H2O2 decomposes to gives 1 mole of O2

0.0168moles of H2O2 decomposes to gives = 1*0.0168/2   = 0.0084 moles of O2

P = 5 bar = 5*0.986923atm   = 4.934615atm

T = 27+273 = 300K

n = 0.0084moles

PV = nRT

V   = nRT/P

      = 0.0084*0.0821*300/4.934615   = 0.042L >>>answer

0.042L of O2 >>>>answer