Login

Welcome, Guest. Please login or register.

March 28, 2024, 07:37:45 pm

Author Topic: Chemistry question  (Read 391 times)  Share 

0 Members and 1 Guest are viewing this topic.

Katherinet123

  • Adventurer
  • *
  • Posts: 10
  • Respect: 0
Chemistry question
« on: February 26, 2020, 12:13:22 pm »
0
Could someone please explain how to do this question! Thankyou

LP gas, which is used as fuel in camping stoves, consists main of propane.
Propane burns in oxygen according to the equation::
C3H8(g) + 502 = 3CO2(g) +HH20(l)

A particular camping stove using propane fuel has a heat output of 22.20KJ per minute. For each minute that the camping stove operates:

a.0.0500g og O2 is consumed
b. 0.440G Of C3H8 is consumed
c. 1.80x10^24 molecules of CO2 are produced
d. 0.720kg oh H20 is produced

angrybiscuit

  • Trendsetter
  • **
  • Posts: 196
  • Respect: +204
Re: Chemistry question
« Reply #1 on: February 26, 2020, 12:36:07 pm »
+3
According to the data booklet, propane releases 50.5 kj of energy per gram and 2220 kj of energy per mole.
Heat of combustion: 50.5 kj g-1
Molar heat of combustion: 2220 kj mol-1

To find out how much propane is consumed per minute we would divide 22.20kj (output of the stove per minute) by the heat of combustion and/or by molar heat of combustion. So:

22.20 kj/ 50.5 kj g-1 = 0.4396 g (0.440 g)
22.20 kj/ 2220 kj mol-1 = 0.01 mol

From this we can see that the answer is B.

For argument's sake, let's go through each answer.

For A:
Per minute, 0.01 mol of propane is consumed. The molar ratios tell us that per mole of propane, 5 mol of oxygen is consumed. Hence in this case, that's 0.05 mol of oxygen consumed.

To find the grams of oxygen we use the formula m(O2) = n x M
m(O2) = 0.05 mol x 16 g mol-1
                               = 0.8 g

Therefore A is wrong.

For C:
Per mole of propane, 3 mole of carbon dioxide is produced. Hence, 0.03 mol of carbon dioxide is produced per minute.
Hence we use the equation N = n x NA
N = 0.03 mol x 6.02 x 1023
    = 1.81 x 1022

Therefore C is wrong

For D:
Per mole of propane, 4 mol of water is produced. Hence, 0.04 mol of water is produced per minute
We use the equation m = n x M
m(H2O) = 0.04 mol x 18 g mol-1
                                  = 0.72 g

Hence D is wrong, due to wrong units
somewhere, something incredible is waiting to be known.
carl sagan