6.02*10^23 is Avagadro's number representing the number of molecules per mole of substance.
A beaker of black powder can be a mixture with different substances (i.e gunpowder: a mixture of sulfur, charcoal, etc.), an element which can probably be carbon (known as black), and a compound as well which can be potassium nitrate. Hence, the answer is D.
Compound is X3Y2.
Hope this helps you!
6.02 x 10^6
Hoped that helped.
Answer:
The answer to your question is below
Explanation:
A.
[H₃O⁺] = 2 x 10⁻¹⁴ M
pH = ?
Formula
pH = - log [H₃O⁺]
Substitution
pH = - log [2 x 10⁻¹⁴]
Result
pH = 13.7
B.
[H₃O⁺] = ?
pH = 3.12
Formula
pH = - log [H₃O⁺]
Substitution
3.12 = - log [H₃O⁺]
![10^{-3.12} = [H_{3} O^{+}]](https://tex.z-dn.net/?f=10%5E%7B-3.12%7D%20%3D%20%5BH_%7B3%7D%20O%5E%7B%2B%7D%5D)
Result
[H₃O⁺] = 7.59 M