A mystery element’s mass spectrum shows it to be 13.92 % Isotope A (219 amu), 72.16 % Isotope B (222 amu), and 13.92 % Isotope C (225 amu).
a. What is the atomic weight of the element?

b. What is the element?

The given element is Radon because its atomic weight is 222 amu.

Explanation:

Given data:

Percentage of A-219 = 13.92%

Percentage of B-222 = 72.16%

Percentage of C-225 = 13.92%

Atomic weight of element = ?

Solution:

Average atomic mass = (abundance of A isotope × its atomic mass) +(abundance of B isotope × its atomic mass) + (abundance of C isotope × its atomic mass)  / 100

Average atomic mass  = (13.92×219)+(72.16×222) + (13.92×225)/100

Average atomic mass =  3048.48 + 16019.52 +3132/ 100

Average atomic mass  = 22200 / 100

Average atomic mass  = 222 amu.

The given element is Radon because its atomic weight is 222 amu.

i'm pretty sure its b i might be wrong though!

a). in this case, dh> 0 and sd> 0. if t becomes larger, the term "-tds" will become more negative. at some point, it is possible that -dts will be more negative than the dh is positive, and the reaction will become spontaneous. this is probably the correct answer, but you should look at all of the other possibilities and make sure of that.