Calculate Moles of Acetylene & O2 in C2H2+O2 Reaction at 60C, 10mmHg

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Discussion Overview

The discussion revolves around calculating the moles of acetylene (C2H2) and oxygen (O2) in a reaction involving acetylene combustion, given specific conditions of temperature, pressure, and the volume of combustion products. The scope includes theoretical calculations and application of gas laws.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Homework-related

Main Points Raised

  • One participant presents the reaction of acetylene with excess oxygen and provides the conditions of the gaseous mixture after the reaction.
  • Another participant asks for the balanced chemical equation and the moles of gases present in the final state, including water.
  • Multiple participants confirm the balanced equation for the reaction as C2H2 + 5/2 O2 -> 2CO2 + H2O and identify the final gases as O2, CO2, and H2O.
  • Some participants propose using Raoult's law to find the mole fraction of water and suggest using the ideal gas law (PV=nRT) to calculate moles of water.
  • There is a reiteration of the approach to find total moles, moles of water, and subsequently the original moles of C2H2 and O2 based on the combustion products.

Areas of Agreement / Disagreement

Participants generally agree on the balanced equation and the approach to calculate moles, but there is no consensus on the specific calculations or the next steps to take.

Contextual Notes

Participants mention assumptions such as ideal gas behavior and the use of Raoult's law, but do not resolve the details of the calculations or the dependencies on specific values.

matthewsyq1995
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Member advised to use the homework template for posts in the homework sections of PF.
Acetylene (C2H2) is reacted with excess O2 in a container. After complete reaction, the volume of the gaseous mixture of the combustion products is 300ft3 at 60C and 10mmHg gauge pressure. P(atm) is 735mmHg. The relative humidity if the product gas is 100% with no condensed water present. Calculate the moles of acetylene and oxygen in the original mixture.

GIven: Saturated vapour pressure of water at 60C is 150mmHg
Pls help!

I don't really know how to continue
 
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What is the balanced chemical reaction equation for the reaction of acetylene with oxygen? How many moles of gases are present in the final state of the system? What are the gases present in the final state of the system? How many moles of water are present in the final state of the system?
 
The equation is C2H2 + 5/2 O2 -> 2CO2 + H2O
Gases in final state would be O2, CO2, and H2O.
I can find the mole fraction of H20 through Raoults law but i don't really know how to continue from there
 
matthewsyq1995 said:
The equation is C2H2 + 5/2 O2 -> 2CO2 + H2O
Gases in final state would be O2, CO2, and H2O.
I can find the mole fraction of H20 through Raoults law but i don't really know how to continue from there
OK. How many moles of water are there? How many moles of C2H2 reacted to produce this amount of water?
 
Chestermiller said:
OK. How many moles of water are there? How many moles of C2H2 reacted to produce this amount of water?
Hmmm ok correct me if I am wrong.
Mole fraction (h2o) = 150/745 = 0.20134
use this to find the moles of h2o using PV= nRT, assuming ideal gas.

use n to find moles of c2h2 and o2 in original mixture.
 
matthewsyq1995 said:
Hmmm ok correct me if I am wrong.
Mole fraction (h2o) = 150/745 = 0.20134
use this to find the moles of h2o using PV= nRT, assuming ideal gas.

use n to find moles of c2h2 and o2 in original mixture.
Correct.

First find total number of moles. Then get moles of h20. From this get original moles of c2h2. From this get moles of co2. From this info, get original moles of o2.
 
Chestermiller said:
Correct.

First find total number of moles. Then get moles of h20. From this get original moles of c2h2. From this get moles of co2. From this info, get original moles of o2.

Alright! thnks!
 

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