A diver breathing heliox with an oxygen composition of 5.0% wants to adjust the total pressure so that P_(O_2)= “0.21 atm”. What must the total pressure be?

The total pressure must be equal to 4.2 atm.

Heliox is a mixture of just two gases, helium and oxygen, so the total pressure in the tank must equal to the of the helium plus the of oxygen – this is known as Dalton’s Law of partial pressures.

Mathematically, this can be written as

##P_”total” = P_”oxygen” + P_”helium”##

A more useful way of writing a relationship between the total pressure exerted by a gaseous mixture and the partial pressure of its individual components is to use something called the mole fraction.

For a gaseous mixture, the mole fraction is used to express the ratio between the number of moles of a gas and the total number of moles present in the mixture.

This means that you can write

##P_”oxygen” = chi_”oxygen” * P_”total”##

In other words, the partial pressure of the oxygen will be equal to its mole ratio multiplied by the total pressure of the mixture.

In your case, you know that oxygen represents 5.0% of the mixture, the rest being helium. To make the calculations easier, you can assume that your mixture contains a total of 100 moles.

This means that your mixture contains 5 moles of oxygen (5% of 100 is 5). Therefore, the mole fraction of oxygen will be

##chi_”oxygen” = (5cancel(“moles”))/(100cancel(“moles”)) = “0.05”##

As a result, the total pressure of the mixture has to be

##P_”total” = P_”oxygen”/chi_”oxygen” = “0.21 atm”https://studydaddy.com/”0.05” = color(green)(“4.2 atm”)##

fraction of helium, for example, would be 0.95, because helium makes up 95% of the mixture. Its partial pressure would be

##P_”helium” = chi_”helium” * P_”total” = 0.95 * “4.2 atm” = “3.99 atm”##

Notice that this is what you get when you use

##P_”helium” = P_”total” – P_”oxygen” = 4.2 – 0.21 = “3.99 atm”##







Calculate Your Essay Price
(550 words)

Approximate price: $22

Calculate the price of your order

550 words
We'll send you the first draft for approval by September 11, 2018 at 10:52 AM
Total price:
$26
The price is based on these factors:
Academic level
Number of pages
Urgency
Basic features
  • Free title page and bibliography
  • Unlimited revisions
  • Plagiarism-free guarantee
  • Money-back guarantee
  • 24/7 support
On-demand options
  • Writer’s samples
  • Part-by-part delivery
  • Overnight delivery
  • Copies of used sources
  • Expert Proofreading
Paper format
  • 275 words per page
  • 12 pt Arial/Times New Roman
  • Double line spacing
  • Any citation style (APA, MLA, Chicago/Turabian, Harvard)

Our guarantees

Delivering a high-quality product at a reasonable price is not enough anymore.
That’s why we have developed 5 beneficial guarantees that will make your experience with our service enjoyable, easy, and safe.

Money-back guarantee

You have to be 100% sure of the quality of your product to give a money-back guarantee. This describes us perfectly. Make sure that this guarantee is totally transparent.

Read more

Zero-plagiarism guarantee

Each paper is composed from scratch, according to your instructions. It is then checked by our plagiarism-detection software. There is no gap where plagiarism could squeeze in.

Read more

Free-revision policy

Thanks to our free revisions, there is no way for you to be unsatisfied. We will work on your paper until you are completely happy with the result.

Read more

Privacy policy

Your email is safe, as we store it according to international data protection rules. Your bank details are secure, as we use only reliable payment systems.

Read more

Fair-cooperation guarantee

By sending us your money, you buy the service we provide. Check out our terms and conditions if you prefer business talks to be laid out in official language.

Read more

Order your essay today and save 10% with the coupon code: best10