What is the average atomic mass of hafnium given the following abundance information on the isotopes? [Hf-176 (mass 176 amu) has an abundance of 5%]
[Hf-177 (mass 177 amu) has an abundance of 19%]
[Hf-178 (mass 178 amu) has an abundance of 27%]
[Hf-179 (mass 179 amu) has an abundance of 14%]
[Hf-180 (mass 180 amu) has an abundance of 35%]

178.55

Explanation:

176 × 0.05+ 177 × 0.19 + 178 × 0.27 + 179 × 0.14 + 180 × 0.35 = 178.55

the correct answer is b. a strong acid completely dissociates to its ions when dissolved in water. completely dissociates to and ions. a is incorrect because does not fully ionize to and ions and some remain as the compound . c and d are incorrect because, and do not fall into the category of bronsted lowry acids. a bronsted lowry acid is a proton donor and since both molecules do not have a proton to donate they are not bronsted lowry acids. likewise,   if we use the lewis acid definition, they cannot be acids. a lewis acid is an electron pair acceptor. both and have a complete octet so can not accept any electrons which disqualifies them as acids.