April 03, 2020, 08:08:05 PM
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### Topic: The combustion reactions of ethene and ethin  (Read 438 times)

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#### Xhevin

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##### The combustion reactions of ethene and ethin
« on: March 26, 2020, 07:34:44 AM »
The combustion reactions of ethene and ethin are given:
C2H4 + 302 = 2CO2 +2 H20
H= -6787Kj

2 C2H2 +5 02 = 4CO2 +2 H20
H= -2599 Kj

Find how much mole of ethene and ethin the mixture with mass= 218gram has If from combustion of this mixture were released 10955.5 Kj.

I have a test and this is the only problem I can not understand because my teacher hasn't explained (coronavirus). Sorry for the bad translation. Thanks in advance.

#### Babcock_Hall

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##### Re: The combustion reactions of ethene and ethin
« Reply #1 on: March 26, 2020, 07:54:43 AM »
It is a forum rule that you must show your attempt before we can help you.  Perhaps you could start by writing an equation involving the masses of ethene and ethyne.

#### Xhevin

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##### Re: The combustion reactions of ethene and ethin
« Reply #2 on: March 26, 2020, 08:33:50 AM »
It is a forum rule that you must show your attempt before we can help you.  Perhaps you could start by writing an equation involving the masses of ethene and ethyne.
I think I solved it But i am not sure.   I got  n¹=6.4 mole  and n²=1.46

#### AWK

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##### Re: The combustion reactions of ethene and ethin
« Reply #3 on: March 26, 2020, 08:39:58 AM »
It's easy to check.
AWK

#### Xhevin

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##### Re: The combustion reactions of ethene and ethin
« Reply #4 on: March 26, 2020, 08:47:19 AM »
It's easy to check.
How can I do that

#### Xhevin

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##### Re: The combustion reactions of ethene and ethin
« Reply #5 on: March 26, 2020, 08:49:10 AM »
It's easy to check.
I am wrong again. Been here for the past 3 hours lol

#### AWK

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##### Re: The combustion reactions of ethene and ethin
« Reply #6 on: March 26, 2020, 08:56:11 AM »
Look at the numbers. 218/26 (acetylene) ~ 8.5.
This amount during combustion gives more than 10,000 KJ.
This means you have about 8 moles of C2H2 and nearly traces of C2H4.
AWK

#### Xhevin

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##### Re: The combustion reactions of ethene and ethin
« Reply #7 on: March 26, 2020, 09:10:02 AM »
Look at the numbers. 218/26 (acetylene) ~ 8.5.
This amount during combustion gives more than 10,000 KJ.
This means you have about 8 moles of C2H2 and nearly traces of C2H4.
Why 26? There is  2C2H2 so it should be 52.

#### AWK

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##### Re: The combustion reactions of ethene and ethin
« Reply #8 on: March 26, 2020, 09:22:43 AM »
2·26=52
AWK

#### MNIO

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##### Re: The combustion reactions of ethene and ethin
« Reply #9 on: March 26, 2020, 12:48:30 PM »
how did you calculate the moles of ethene and ethyne... (note the spelling)?

#### Enthalpy

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##### Re: The combustion reactions of ethene and ethin
« Reply #10 on: March 27, 2020, 05:52:59 AM »
C2H4 + 3 02  2 CO2 + 2 H20  ΔH= -6787 kJ

2 C2H2 + 5 02  4 CO2 + 2 H20  ΔH= -2599 kJ

I can't believe two acetylenes produce less heat than one ethylene. Check the figures.

#### AWK

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##### Re: The combustion reactions of ethene and ethin
« Reply #11 on: March 27, 2020, 07:36:18 AM »
The heat of combustion of acetylene (for 2 moles) is correct. This heat of ethylene combustion is wrong.
AWK

#### Helly

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##### Re: The combustion reactions of ethene and ethin
« Reply #12 on: March 29, 2020, 02:21:31 PM »
A = mole of ethylene
B = mole of ethyne

A(6787Kj) + B(2599) = 10955.5Kj
A(28) + B(52) = 218 g

#### AWK

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##### Re: The combustion reactions of ethene and ethin
« Reply #13 on: March 29, 2020, 02:49:23 PM »
The heat of combustion of 1 mol ethylene is 1411 kJ/mol
The molecular mass of acetylene is 26
AWK

#### Helly

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##### Re: The combustion reactions of ethene and ethin
« Reply #14 on: Yesterday at 06:05:44 AM »
Ok sir. Even hough 2C2H2 still 26 g/mol