Homework Help Forum: chemistry

Posted by Anonymous on Tuesday, October 6, 2009 at 9:07pm.

2H2O2 --> 2H2O +O2 If a 250mL bottle of hydrogen peroxide solution containing 3% H2O (by mass) completely decomposed how many liters of gas would it generate. Assume that one mole of gas occupies a volume of 22.4 L and that the density of the solution is 1 g/mL.

• chemistry - brandon, Tuesday, October 6, 2009 at 9:18pm

  so basically since you have 250ml of solution, therefore you have 250g of H2O2 (i think you might have put in a typo)... now you calculate number of moles of H2O2 (the molar mass is approx 34 g/mol) with the formula number of moles = mass/molar mass now use mole ratios to find out that its 2:1 so the number of moles of O2 is half that of the number of moles of H2O2... divide the number of moles of peroxide by two and multiply by 22.4L that should be your answer

  
  

• chemistry - DrBob222, Tuesday, October 6, 2009 at 9:19pm

  3% by mass means there are 3 g H2O2/100 g solution. With a density of 1 g/mL, 100 g solution will occupy 100 mL; therefore, we have 3 g H2O2/100 mL or 3 x (250/100) = 7.5 g H2O2 in the bottle. Convert 7.5 g H2O2 to moles. Convert moles H2O2 to moles O2 using the equation. Volume = 22.4 L/mole x #moles = ?? Post your work if you get stuck.

  
  

• chemistry - brandon, Tuesday, October 6, 2009 at 9:20pm

  ahhh crud sorry i forgot about the % of H2O2 go with DrBob

  
  

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