Balancing Chemical Equations: How to Calculate Unknown Products

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Discussion Overview

The discussion revolves around a chemistry problem involving the balancing of a chemical equation and the calculation of unknown products formed during a reaction. Participants explore the stoichiometry of the reaction between methane (CH4) and oxygen (O2) to determine the mass of water (H2O) produced.

Discussion Character

  • Homework-related
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant expresses confusion about the problem and seeks guidance on how to approach it.
  • Another participant questions whether methane reacts with CO2 or O2, clarifying that it must be O2.
  • Participants suggest starting with the molecular weights of the reactants and products to find the number of moles involved.
  • There is a discussion about the necessity of balancing the chemical equation before proceeding with calculations.
  • A participant provides a detailed solution, including the balanced equation and calculations, concluding that 54 g of H2O is produced.
  • Some participants confirm the need to balance the equation and discuss the implications of the law of conservation of mass.

Areas of Agreement / Disagreement

While there is agreement on the need to balance the equation and the approach to solving the problem, the initial confusion about the reaction components indicates some uncertainty. The discussion includes both supportive responses and clarifications, but no consensus on the initial interpretation of the reaction is reached.

Contextual Notes

The discussion highlights the importance of balancing chemical equations and understanding stoichiometry, but it does not resolve all uncertainties regarding the initial problem setup.

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I need help, please!:eek: :bugeye: I am totally and completely lost with this problem. Unfortunately, my book does not give any examples for me to go by.

Here is the problem...

In the following reaction, 24 g of CH4 (methane) react completely with 96 g of O2 to form 66 g of CO2. How many grams of H20 are formed?

CH4 + CO2---->CO2 + 2H2O

Where do I begin on this problem? TIA for any help provided.
 
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Does the methane react with CO2 or O2?

(Sorry, I edited instead of quoted ~ Moonbear :redface:)
 
Last edited by a moderator:
1) You'll need to start out finding the molecular weights of each molecule in your reaction.
2) Then use that information to find the number of moles of starting and ending product.
Hopefully, you'll be able to see from there how you can use your given information to solve for your unknown. If not, come back with your answers to 1 and 2 and we'll help you get to step 3.
 
Mozart said:
Does the methane react with CO2 or O2?
It has to be O2.
 
Would you have to balance the equation first Moonbear? I ask because as it is written there are more oxygen atoms on the products side.
 
Yeah, you would have to balance out the atoms. The mole ratios need to be correct for the stoichiometry.
 
WOW! Thanks for all the friendly postings. I really appreciate it. However, this is simple Physical Science 8th grade style. We haven't gotten into the complicated stuff quite yet. At any rate, I ended up figuring it out for myself. To my surprise, my science teacher said I did everything correctly. Here is what I came up with, just in case there are other posters working on the same type of problem.

Here are the knowns:
mass of CH4= 24g
mass of O2= 96g
mass of CO2= 66g
mass of reactants=mass of products

CH4 + 2O2---->CO2 + 2H2O
24 g + 96 g ---->66 g + ?
120 g – 66 g = 54 g
24 g + 96 g ---->66 g + 54 g
H20= 54 g

Also, this follows the law of conservation of mass, meaning the mass of all substances that are present before a chemical change equal the mass of all the substances that remain after the change.
 
Mozart said:
Would you have to balance the equation first Moonbear? I ask because as it is written there are more oxygen atoms on the products side.
Looks like he already got the answer, but just to wrap things up...in answer to your question, yes.
 

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