Chemical Forums
Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: xtullyx16 on September 26, 2010, 08:52:28 PM
-
#1
Gaseous Butane (C4H10) is compressed and used as a liquid fuel in disposable cigarette lighters and lightweight camping stoves. Suppose a lighter contains 5.00mL butane ( density = .579 g/mL)
A. Write and balance the combustion reaction of butane.
2 (C4H10) + 13 O2 ------> 8 CO2 + 10 H20
B. How many grams of oxygen are needed to burn the butane completely?
C. How many moles of CO2 form when all the butane burns?
D. How many total molecules of gas form when the butane burns completely?
#2
Sodium borohydride (NaBH4, sold commercially as a detergent called Borax) is used industrially in many organic syntheses. One way to prepare it is by reacting sodium hydride with gaseous diborane (B2H6). Assuming a 95.5% yield, how many grams of NaBH4 can be prepared by reacting 7.88g of sodium hydride and 8.12g of diborane?
-
You have to show your attempts at solving the question to receive help. This is a forum policy.
There is enough information and it is a pretty simple stoichiometry problem.
What would you need to calculate oxygen mass?
-
You have to show your attempts at solving the question to receive help. This is a forum policy.
There is enough information and it is a pretty simple stoichiometry problem.
What would you need to calculate oxygen mass?
Well you need the density and volume.. sorry it seems so easy ha. But I only have density of butane and volume of Butane. I think i can solve the last problem after my class today. Ill give it a try and post the results
-
#1
Gaseous Butane (C4H10) is compressed and used as a liquid fuel in disposable cigarette lighters and lightweight camping stoves. Suppose a lighter contains 5.00mL butane ( density = .579 g/mL)
A. Write and balance the combustion reaction of butane.
2 (C4H10) + 13 O2 ------> 8 CO2 + 10 H20
B. How many grams of oxygen are needed to burn the butane completely?
C. How many moles of CO2 form when all the butane burns?
D. How many total molecules of gas form when the butane burns completely?
#2
Sodium borohydride (NaBH4, sold commercially as a detergent called Borax) is used industrially in many organic syntheses. One way to prepare it is by reacting sodium hydride with gaseous diborane (B2H6). Assuming a 95.5% yield, how many grams of NaBH4 can be prepared by reacting 7.88g of sodium hydride and 8.12g of diborane?
*** gave it a try, I only got so far till I forgot where to go from there.
7.88g 2NaH( 2 mol/ 48)(2 mol NaBH4/2 mol 2NaH)(76g/ 2 mol NaBH4) = 12.48g NaBH4
8.12g B2H6( 1mol/ 28g B2H6)(2 mol NaBH4/ 1 mol B2H6)(76g/2 Mol) = 22.04g NaBH4
Thus, the limiting reactant is 2NaH..
-
Seems to me like you have no idea what stoichiometry is.
http://www.chembuddy.com/?left=balancing-stoichiometry&right=stoichiometric-calculations
-
#1
Gaseous Butane (C4H10) is compressed and used as a liquid fuel in disposable cigarette lighters and lightweight camping stoves. Suppose a lighter contains 5.00mL butane ( density = .579 g/mL)
A. Write and balance the combustion reaction of butane.
2 (C4H10) + 13 O2 ------> 8 CO2 + 10 H20
B. How many grams of oxygen are needed to burn the butane completely?
C. How many moles of CO2 form when all the butane burns?
D. How many total molecules of gas form when the butane burns completely?
#2
Sodium borohydride (NaBH4, sold commercially as a detergent called Borax) is used industrially in many organic syntheses. One way to prepare it is by reacting sodium hydride with gaseous diborane (B2H6). Assuming a 95.5% yield, how many grams of NaBH4 can be prepared by reacting 7.88g of sodium hydride and 8.12g of diborane?
Sodium borohydride is not Borax.
-
#1
Gaseous Butane (C4H10) is compressed and used as a liquid fuel in disposable cigarette lighters and lightweight camping stoves. Suppose a lighter contains 5.00mL butane ( density = .579 g/mL)
A. Write and balance the combustion reaction of butane.
2 (C4H10) + 13 O2 ------> 8 CO2 + 10 H20
B. How many grams of oxygen are needed to burn the butane completely?
C. How many moles of CO2 form when all the butane burns?
D. How many total molecules of gas form when the butane burns completely?
#2
Sodium borohydride (NaBH4, sold commercially as a detergent called Borax) is used industrially in many organic syntheses. One way to prepare it is by reacting sodium hydride with gaseous diborane (B2H6). Assuming a 95.5% yield, how many grams of NaBH4 can be prepared by reacting 7.88g of sodium hydride and 8.12g of diborane?
Sodium borohydride is not Borax.
Well thats what my sheet says, I cant dispute that
-
Seems to me like you have no idea what stoichiometry is.
http://www.chembuddy.com/?left=balancing-stoichiometry&right=stoichiometric-calculations
Im guessing you're concluding that because my stoichemetry isn't exactly text book perfect but my method, has the same answer as the book's.. I have the same ratio...
Im not looking for more grief on my practices, Im looking for help, and I've not yet had anyone lend a helping hand here?!
-
No, my conclusion had its source in the fact that you omitted obvious steps when approaching the first problem, and you suggested you would calculate amount of oxygen using completely unrelated formula. I see you approached borohydride question using stoichiometric ratios and correctly - you just have to apply yield percentage to your result now. (Oh, an whoever wrote the question - borax vs borohydride thing - really should either learn more or pay more attention to what they are doing).
Back to 1st question:
Do you know what mass of butane reacted?
How many moles it is?
How many moles of oxygen it reacts with?
What mass it is?
-
No, my conclusion had its source in the fact that you omitted obvious steps when approaching the first problem, and you suggested you would calculate amount of oxygen using completely unrelated formula. I see you approached borohydride question using stoichiometric ratios and correctly - you just have to apply yield percentage to your result now. (Oh, an whoever wrote the question - borax vs borohydride thing - really should either learn more or pay more attention to what they are doing).
Back to 1st question:
Do you know what mass of butane reacted?
How many moles it is?
How many moles of oxygen it reacts with?
What mass it is?
Mass- 58.04 g C4H10?
Moles- 1 mol C4H10
Mass- 32g o2
Moles- 13 mol o2
Question pertaining to #2 is what is the theoretical yield or Actual Yield? Or is this like an equation (ty/ay) * 100 = 95.5%
-
Mass- 58.04 g C4H10?
No. This is molar mass, not mass of the butane. Please reread the question.
(ty/ay) * 100 = 95.5%
Quite the opposite - ay/ty * 100 = 95.5%