Hydrogen peroxide is used as a cleaning agent in the treatment of cuts and abrasions for several reasons. it is an oxidizing agent that can directly kill many microorganisms; it decomposes upon contact with blood, releasing elemental oxygen gas (which inhibits the growth of anaerobic microorganisms); and it foams upon contact with blood, which provides a cleansing action. in the laboratory, small quantities of hydrogen peroxide can be prepared by the action of an acid on an alkaline earth metal peroxide, such as barium peroxide. bao2(s) + 2 hcl(aq) h2o2(aq) + bacl2(aq) what amount of hydrogen peroxide should result when 1.49 g of barium peroxide is treated with 25.1 ml of hydrochloric acid solution containing 0.0279 g of hcl per ml? webassign will check your answer for the correct number of significant figures. 0.299 correct: your answer is correct. g what mass of which reagent is left unreacted? webassign will check your answer for the correct number of significant figures. 0.0367 incorrect: your answer is incorrect. g hcl bao2 correct: your answer is correct.

Given:

BaO2(s) + 2 HCl(aq) => H2O2(aq) + BaCl2(aq) 

Mass of barium peroxide = 1.49 g Volume of HCl solution = 25.1 mLConcentration of HCl solution = 0.0279 g HCl per mL

Solution: To determine the amount of hydrogen peroxide that would be produced, we use need to determine which is the limiting reactant and use the initial amount of this reactant for the calculations. 

0.0279 g HCl / mL ( 25.1 mL ) ( 1 mol HCl / 36.46 g HCl) ( 1 mol BaO2 / 2 mol HCl ) = 0.0096 mol BaO2 needed
1.49 g BaO2 ( 1 mol / 169.3 g BaO2 ) ( 2 mol HCl / 1 mol BaO2 ) = 0.0176 mol HCl needed

Therefore, the limiting reactant would be barium peroxide since it is consumed completely first in the reaction.

1.49 g BaO2 ( 1 mol BaO2 / 169.3 g BaO2 ) ( 1 mol H2O2 / 1 mol BaO2 ) ( 34.02 g H2O2 / 1 mol H2O2 ) = 0.299 g H2O2

The answer to your question really depends on three things: how much water you have, how cold it is to start out, and how cold the things around it are. water actually freezes when it gets to 32 degrees fahrenheit (0 degrees celsius), but the time it takes to get there may be different.  let's start with the first. if you take two glasses, and fill one with a tiny bit of water, and the other about halfway, then put them both in the freezer, the one with less water will freeze first (you can try this at home, but i recommend using plastic cups and not glass ones).  now let's move on to the second part. let's say you have two glasses, and you fill one with really cold water that has been in the refrigerator, and the other with really hot water from the sink. if you put both of them in the freezer, the one that started out colder will freeze first.  for the third part, let's imagine that you have two glasses with the same amount of water in them, and the water is at the same temperature. imagine putting one outside on a really really cold day in georgia, and having a friend in alaska put one outside on the same day. since it would be so much colder in alaska, the glass of water there would freeze before yours.  so, if you took a tiny bit of really cold water in a glass, and put it outside on a cold day in alaska, it would freeze a lot faster than a big glass of hot water outside on a cold day in georgia.