Posted by Sam on Saturday, December 1, 2012 at 12:11am.
You are given 2.677 g of a mixture of KClO3 and KCl. When heated, the KClO3 decomposes to KCl
2 KClO3 (s) → 2 KCl (s) + 3 O2 (g),
and 605 mL of O2 is collected over water at 28 °C. The total pressure of the gases in the collection flask is
763 mm Hg. What is the weight percentage of KClO3 in the sample?
The formula weight of KClO3 is 122.55 g/mol. The vapor pressure of water at 28 °C is 28.3 mm Hg
Chemistry - DrBob222, Saturday, December 1, 2012 at 12:26am
PV = nRT
P = [(763-28.3)/760] atm.
V = 0.605 is correct.
Substitute R and T and solve for n = number of mols O2.
Convert mols O2 to mols KClO3 using the coefficients in the balanced equation. Then convert mols KClO3 to grams. g = mols x molar mass.
Then %KClO3 = (mass KClO3/2.677)*100 = ?
Chemistry - Sam, Saturday, December 1, 2012 at 1:01am
=0.000233592 x (2/3) = 0.000155728 x 122.5 g
=0.019076722/2.677 x 100 = 0.710 %
This result seems really small...what have i done incorrect?
Chemistry - DrBob222, Saturday, December 1, 2012 at 1:04am
Yes, and it IS too small.
R = 0.08206 and not 8.314 when P is in atmospheres. Correct that and see if the answer is about 72%
Answer This Question
More Related Questions
- Chemistry - You are given 1.226 g of a mixture of KClO3 and KCl. When heated, ...
- Chemistry - Consider the thermal decomposition of potassium chlorate. 2 KClO3(s...
- Chemistry - Consider the thermal decomposition of potassium chlorate. 2 KClO3 (s...
- chemistry - . A 0.428-gram sample of a mixture of the solids, KCl and KClO3, is ...
- Chemistry Help! - If 100 grams of KClO3 are heated to form KCl and O2 according ...
- Chemistry - If 237 mL of O2, measured at STP, are obtained by the decomposition ...
- chemistry - If 267 mL of O2, measured at STP, are obtained by the decomposition ...
- Chemistry - When heated, KClO3 decomposes into KCl and O2. If this reaction ...
- chemistry - when heated, kclo3 decomposes into kcl ad 02. 2kclo3--> 2kcl+3o2 ...
- chemistry - What volume of oxygen gas can be collected at 1.26 atm pressure and ...