An unknown gas diffuses 0.25 times as fast as He. What is the molecular mass of the unknown gas?

64 amu

Explanation:

An unknown gas (X) diffuses 0.25 times as fast as He. Mathematically, we can say that the rate of diffusion of X (rX) is 0.25 that of He.

rX = 0.25 rHe

rX/rHe = 0.25

Given the molecular mass of He (MHe) is 4.00 amu, we can calculate the molecular mass of X using Graham's law of diffusión.

rX/rHe = √(MHe/MX)

0.25 = √(4.00 amu/MX)

MX = 64 amu

-be a crystalline solid

- be soluble in water

-conduct electricity

hope this : )

out of these options:

ability to burn paper

pure sodium reacting violently with water

the boiling point of water

helium does not tend to react with anything

i would say this is a physical property:

helium does not tend to react with anything

why? :

i said helium does not tend to react with anything because well, it reacts to ! but ability to burn paper, pure sodium reacting violently with water, & the boiling point of water are chemical or

physical properties: the properties of a substance that can be observed without changing the chemical makeup of the substance

chemical properties: properties of a substance relating to the chemical nature and reactivity of the substance