Answer:
35.8 u
Explanation:
The atomic mass of Cl is the weighted average of the atomic masses of its isotopes.
We multiply the atomic mass of each isotope by a number representing its relative importance (i.e., its percent abundance).
Atomic mass of Cl-35 = 17p + 18n = 17 × 1.007 u + 18 × 1.009 u
= 17.119 u + 18.162 u = 35.28 u
Atomic mass of Cl-37 = 17p + 20n = 17 × 1.007 u + 20 × 1.009 u
= 17.119 u + 20.180 u = 37.30 u
Set up a table for easy calculation.
0.755 × 35.28 u = 26.64 u
0.245 × 37.30 u = 9.138 u
TOTAL = 35.8 u
Note: The actual atomic mass of Cl is 35.45 u.
The calculated value above is incorrect because
(a) the given isotopic percentages are incorrect and
(b) the protons and neutrons have less mass when they are in the nucleus than when they are free. Thus, the calculated masses of Cl-35 and Cl-37 are too high.
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NH₄CN is a salt formed from weak base NH₄OH and weak acid HCN so that it undergoes complete hydrolysis
<h3>Further explanation</h3>
The hydrolysis process is a term used for the reaction of substances with water
There are 3 types of hydrolysis salts
1.Salt from strong acids and strong bases does not undergo hydrolysis so that the pH of the neutral solution = 7
2.Salt from strong acids and weak bases (pH <7) or from strong bases and weak acids (pH> 7) will be partially / partially hydrolyzed
3.Salt from weak acids and weak bases (pH depends on the value of Ka and Kb) will be completely hydrolyzed
NH₄CN is a salt formed from weak base NH₄OH and weak acid HCN so that it undergoes complete hydrolysis
NH₄OH + HCN⇒NH₄CN+H₂O
Can be formulated :
![\tt [H^+]=\sqrt{\dfrac{Kw\times Ka}{Kb} }](https://tex.z-dn.net/?f=%5Ctt%20%5BH%5E%2B%5D%3D%5Csqrt%7B%5Cdfrac%7BKw%5Ctimes%20Ka%7D%7BKb%7D%20%7D)
Ka> Kb then [H +]> 7 and pH <7 ⇒ acidic
Ka <Kb then [H +] <7 or pH> 7 ⇒alkaline
Ka = Kb then pH = 7 ⇒neutral
Answer:
142.04 g/mol is the answer to your question.
