You will be using 25.00 mL of 3.00% by mass solution ({mass H_2O_2/mass solution

Question

You will be using 25.00 mL of 3.00% by mass solution ({mass H_2O_2/mass solution} * 100) of hydrogen peroxide. Assume the density of this solution is 1.000 g/mL. If all of hydrogen peroxide decomposes to water and oxygen according to the reaction 2 H_2O (aq) doubleheadarrow 2 H_2O (I) + O_2 (g) What is the total volume of oxygen gas generated if the temperature is 24 degree C and the pressure is 770 Torr (760 Torr 1 = atm) (R = 0.08206 L middot atm/K middot mol) (At this point you can ignore the effect of water vapor).

Explanation / Answer

2H2O2 (aq) <--> 2H2O (l) + O2 (g)

we use 25 ml of 3 % H2O2    which means 3g H2O2 per 100 g solution.

solution density = 1g/ml , hence solution volume = mass / density = 100 g / 1g/ml = 100 ml

H2O2 mass = ( 3g /100ml) x 25ml = 0.75 g

H2O2 moles = mass / Molar mass of H2O2

                  = 0.75 g / ( 34 g/mol) = 0.02206

as per reaction O2 moles produced = ( 1/2) H2O2 moles = ( 1/2) x 0.02206 = 0.01103

we use PV = nRT equation to find volume of gas ,

P = 770 torr = 770 /760 atm = 1.013 atm ,

T = 24 C = 24 + 273 = 297 K

1.013 atm x V = 0.01103 mol x 0.08206 liter atm/molK x 297 K

V = 0.2654 L = 265.4 ml

Related Questions

Navigate

• Browse (All)
• Browse Y
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.