Find the molar percentage....

In summary, molar percentage is the percentage by weight of a substance in a solution, calculated by dividing the molar mass of the substance by the total molar mass of the solution and multiplying by 100. It differs from mass percentage as it takes into account the molar mass of the substance, making it a more accurate measure of concentration. Molar percentage is important in chemistry as it helps scientists accurately measure concentration, which is crucial in many experiments and reactions. It is calculated by dividing the molar mass of the substance by the total molar mass of the solution and multiplying by 100. Molar percentage is commonly used in titrations, analyzing mixtures, determining purity, and understanding solution properties in scientific research.
  • #1
JeremyC
3
1

Homework Statement



The total pressure of a mixture of oxygen and hydrogen is 1.00 atm. The mixture is ignited and the water produced is removed. The remaining gas is pure hydrogen and exerts a pressure of 0.34 atm when measured in the same volume and at the same temperature as the original mixture. What was the composition of the original mixture in mole percent?

Homework Equations


2H2 +O2 ---> 2H2O

3. The Attempt at a Solution [/B]

1atm - 0.34atm = 0.66atm H2O

for every 1 mol of H2 that reacts, 2 mols of H2 react so,
0.44atm of the water is H2
0.22 atm of the water is O2

0.34atm +0.44atm = 0.78atm H2O
0.22atm O2

78% of the mixture is H2
22% of the mixture is O2

Can someone check this?
 
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  • #2
I think that is quite OK.

However for this sort of calculaction if you haven't got anyone to check it for you you can do it yourself. You just take your conclusions and pose the inverse question, suppose you have this initial composition (which is your answer) how much H2 would you get from it if you reacted it? - the answer should correspond to the first question.
 
  • #3
Hello Jeremy, :welcome: (somewhat belated).

PF isn't really in the business of stamp-approving answers -- it would only create tension between PF and teachers in general -- especially in cases where opinions differ. Read the guidelines ...

However, in your case there is little room for doubt, uncertainty and fear. So I wonder why you ask at all ?
 

1. What is molar percentage?

Molar percentage refers to the percentage by weight of a particular substance in a given solution or mixture. It is calculated by dividing the molar mass of the substance by the total molar mass of the solution and multiplying by 100.

2. How is molar percentage different from mass percentage?

Molar percentage takes into account the molar mass of a substance, while mass percentage only considers the mass of the substance. Molar percentage is a more accurate measure of the concentration of a substance in a solution.

3. Why is molar percentage important in chemistry?

Molar percentage is important because it allows scientists to accurately measure the concentration of a substance in a solution. This information is crucial in many chemical reactions and experiments.

4. How do you calculate molar percentage?

To calculate molar percentage, you need to know the molar mass of the substance and the total molar mass of the solution. Divide the molar mass of the substance by the total molar mass of the solution and multiply by 100 to get the molar percentage.

5. What are some common uses of molar percentage in scientific research?

Molar percentage is often used in titrations to determine the concentration of a solution. It is also used in analyzing the composition of mixtures and in determining the purity of a substance. Additionally, molar percentage is important in chemical reactions and in understanding the properties of solutions.

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