An isotope has three forms. 30% have a mass of 15 amu, 20% have a mass of 16 amu and 50% have a mass of 17 amu. What is the average atomic mass of this element?
a. 15.8 amu
b. 16.0 amu
c. 16.2 amu
d. 16.4 amu

Consider the four elements above. which one of these elements will combine with oxygen in a 1: 1 ratio?

Phosphoric acid is a triprotic acid ( =6.9×10−3 , =6.2×10−8 , and =4.8×10−13 ). to find the ph of a buffer composed of h2po−4(aq) and hpo2−4(aq) , which p value should be used in the henderson–hasselbalch equation? p k a1 = 2.16 p k a2 = 7.21 p k a3 = 12.32 calculate the ph of a buffer solution obtained by dissolving 18.0 18.0 g of kh2po4(s) kh 2 po 4 ( s ) and 33.0 33.0 g of na2hpo4(s) na 2 hpo 4 ( s ) in water and then diluting to 1.00 l.

Most metamorphosis processes take place