Chemistry issue x2

[xtullyx16]

Yet again critical thinking worksheet is giving me fits! More fits than last time atleast!

#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?

[honda400ex2003]

my guess is that

b) 5mL*.579 g/mL=2.895g

ratio

2/2.895 for the butane = to 13/x for o2

so x is 18.81 grams of oxygen

c) find molar mass of O2

grams/molar mass=x/1 mole

so 18.81 g/32 g/mol=.588 moles of O2

D) you would get 11.58 grams of CO2

get moles 11.58/44.01 g/mole

=.263 moles of CO2

*** now i am no expert at chem it has been a couple of years since i did it so this may not be correct. worth a shot though and it is something to put down if you are still unsure and have to turn it in. lol good luck, report back if i am right or not. lol steve

[honda400ex2003]

#2

7.88+8.12*.955=15.28 grams lol completely unsure about that one. hehe

steve

[xtullyx16]

Originally posted by honda400ex2003
#2

7.88+8.12*.955=15.28 grams lol completely unsure about that one. hehe

steve

Thanks steve but yeah that answer is wrong.. Ill post up number 2 in a min.. I figured that one out.. but I was still lost on problem 1

[honda400ex2003]

did i do the first right? I figured the second was wrong lol steve