Atank containing both hf and hbr gases developed a leak. the ratio of the rate of effusion of hf to the rate of effusion of hbr is
a. 0.247
b. 2.01
c. 4.04
d. 16.3
e. 0.497

Option (B) is the correct answer.

Explanation:

According to the Graham's law, rate of effusion of a gas is inversely proportional to the square root of molar mass of the gas.

Mathematically,   Rate of effusion =

where,   M = molar mass of gas

As molar mass of HF is 20.01 g/mol and molar mass of HBr is 80.91 g/mol. Therefore, calculate the ratio of rate of effusion of HF to the rate of effusion of HBr as follows.

        =

                    =  

                    = 2.009

                    = 2.01 (approx)

Thus, we can conclude that ratio of the rate of effusion of HF to the rate of effusion of HBr is 2.01.

answer: atomic mass was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.

explanation:

originally atomic mass was used to arrange elements on the periodic table from left to right in a row. each column then shows similar properties of elements of a group.

in modern periodic table, the atoms are arranged in increasing atomic number. as atomic number represents the number of protons in an atom which is unique for every atom.