Balancing Chemical Reaction

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Emily Mendez 4C
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Joined: Wed Nov 14, 2018 12:19 am

Balancing Chemical Reaction

Postby Emily Mendez 4C » Wed Oct 02, 2019 9:07 pm

I'm having trouble on solving a question on the pre-assessment module. I don't know if anyone can help me out on what are the steps I'm suppose to take to solve it. I would really appreciate it. I'm completely confused.

During a summer camping weekend 4 moles of butane (C4H10) gas were used for cooking. Chose the right balanced equation for the combustion of 4 moles of butane gas. What is the net number of moles of gas produced?

Thank you!

Gerald Bernal1I
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Re: Balancing Chemical Reaction

Postby Gerald Bernal1I » Wed Oct 02, 2019 9:18 pm

The problem wants you to write the chemical equation out yourself rather than provide it. This is a combustion reaction since butane is being burned, therefore for any combustion reaction the gas would react with O2 and produce CO2 and H2O. For this problem the equation would be 4C4H10 + O2 --> CO2 + H2O. From there, you balance this equation and from the molar coefficients you would be able to see how many moles of product are produced. Then you would subtract total number of moles of product from total number of moles of reactant.

Sofia Q
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Re: Balancing Chemical Reaction

Postby Sofia Q » Wed Oct 02, 2019 9:21 pm

Remember the law of conservation of mass while balancing the equation, your number of atoms should be present in the reactants side of the equation should match those in the product side. If yours match like that then you know that you balanced it with the correct coefficients.

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Re: Balancing Chemical Reaction

Postby 605379296 » Wed Oct 02, 2019 9:22 pm

When it comes to combustion questions, the set up for it is usually like this: CxHy +O2---> CO2+H2O, where the x and y are variables. So in this case, you would replace the x and y as 4 and 10, respectively. I balanced the equation and I got this: 4C4H10+26O2---> 16CO2+20H2O. In order to find the net number of moles, there's a formula: sum of coefficient of products- sum of coefficients of reactants. This formula makes sense since you are looking for the net number of moles before and after the reaction. In this case, there's 4+26= 30 reactant moles and 16+20= 36 product moles. So, you then do 36-30=6, resulting in 6 net moles.

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Re: Balancing Chemical Reaction

Postby san_2F » Wed Oct 02, 2019 9:35 pm

For any combustion reaction, butane reacts with oxygen to produce carbon dioxide and water. first balance the equation. After balancing the equation, look at the stoichiometric coefficient in front of oxygen and thats the number of moles of gas produced.

Tai Metzger 3K
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Re: Balancing Chemical Reaction

Postby Tai Metzger 3K » Wed Oct 02, 2019 9:39 pm

I find it easiest to start with the the element that appears only once on each side and work from there, saving the most complicated elements for the end. Additionally, double check your work because it is easy to make mistakes that you don't notice while doing the problem.

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Re: Balancing Chemical Reaction

Postby AndreiRekesh1I » Wed Oct 02, 2019 9:54 pm

For combustion reactions in particular, I find that balancing oxygen last is easiest.

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