Amixture of noble gases [helium (mw 4), argon (mw 40), krypton (mw 83.8), and xenon (mw 131.3)] is at a total pressure of 150 kpa, and a temperature of 500 k. the mixture has the following composition in mole fraction: 0.25 helium, 0.25 argon, 0.25 krypton. determine: (a) the mass fraction of helium. (b) the average molecular weight of the mixture. (c) the total molar concentration. (d) the mass density.

a) 1,6%

b) 64,775 g/mol

c) 3,6×10⁻² M

d) 2,3×10⁻³ g/mL

Explanation:

a) The mass fractium of helium is obtained converting the moles of the four gases to grams with molar weight and then caculating of the total of grams how many are of helium, thus:

Total grams: 1g+10g+20,85g+30,825g= 62,675 g

Mass fraction of helium: × 100 = 1,6%

The mass fraction of Helium is 1,6%

b)  Because the mole fraction of all gases is the same the average molecular weight of the mixture is:

= 64,775 g/mol

c) The molar concentration is possible to know ussing ideal gas law, thus:

= M

Where:

P is pressure: 150 kPa

R is gas constant: 8,3145

T is temperature: 500 K

And M is molar concentration. Replacing:

M = 3,6×10⁻² M

d) The mass density is possible to know converting the moles of molarity to grams with average molecular weight and liters to mililiters, thus:

3,6×10⁻² × × =

2,3×10⁻³ g/mL

I hope it helps!

the correct answer is b. a strong acid completely dissociates to its ions when dissolved in water. completely dissociates to and ions. a is incorrect because does not fully ionize to and ions and some remain as the compound . c and d are incorrect because, and do not fall into the category of bronsted lowry acids. a bronsted lowry acid is a proton donor and since both molecules do not have a proton to donate they are not bronsted lowry acids. likewise,   if we use the lewis acid definition, they cannot be acids. a lewis acid is an electron pair acceptor. both and have a complete octet so can not accept any electrons which disqualifies them as acids.