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.

i look it up online and i'll tell you

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"