A 5.0-liter gas tank holds 2.7 moles of monatomic helium (He) and 0.90 mole of diatomic oxygen (O2), at a temperature of 330 K. The ATOMIC masses of helium and oxygen are 4.0 g/mol and 16.0 g/mol, respectively. What is the ratio of the root-mean-square (thermal) speed of helium to that of oxygen?

Respuesta :

Answer:

This problem can be solved by using the expression

[tex]v_{rms}=\sqrt{\frac{3RT}{M_{m}}}[/tex]

where R is the gas constant, T is absolute temperature and M is the molar mass in kg/mol. By calculating for both Helium and oxygen we have

[tex]v_{rms-He}=\sqrt{\frac{2RT}{M_{He}}}=\sqrt{\frac{2(8.314)(330)}{4*10^{-3}}}=1171.2\frac{m}{s}\\v_{rms-O_{2}}=\sqrt{\frac{2RT}{M_{0_{2}}}}=\sqrt{\frac{2(8.314)(330)}{16*10^{-3}}}=585.6\frac{m}{s}\\\frac{v_{rms-He}}{v_{rms-O_{2}}}=1.999\approx 2[/tex]

Hence, the vrms of the monoatomic helium is two times the vrms of the oxygen

I hope this is useful for you

best regards

Answer:

The ratio is 2:1

Explanation:

Given their atomic masses, Mh = 4.0g/mol and Mo = 16g/mol

Vrms = √(3RT/M)

R and T are constant so Vrms ∝√(1/M)

So (Vrms)Helium/(Vrms)oxygen = √(1/Mh)/√(1/Mo) = √(Mo/Mh)

(Vrms)Helium/(Vrms)oxygen = √(Mo/Mh)

= √(16.0/4.0) = √(4) = 2