Answer:
D
Explanation:
I believe the answer is D because atoms are always seeking to fill up their outer electron shell/valence shell and want to gain a full octet.
Na releases 1 electron to be stable
Cl requires 1 electron to be stable
both are ionic bonded to be stable
3. A
4. B
5. A
6. E
7. A
8. C
9. A
10. B
Some of these were guesses but they were educated guesses. Best of luck. If some of them are wrong I am sorry. <span />
The notation is actually written in this way (shown in the attached picture). The X is the symbol of the element. So, for potassium, the symbol is K. The A represents the mass number of the isotope. In this case, that would be equal to 39. The Z represents the atomic number of potassium, which is 19. Therefore, the symbol for the isotope is:
³⁹₁₉K
Answer:
Final pH: 9.49.
Round to two decimal places as in the question: 9.5.
Explanation:
The conjugate of B is a cation that contains one more proton than B. The conjugate of B is an acid. As a result, B is a weak base.
What's the pKb of base B?
Consider the Henderson-Hasselbalch equation for buffers of a weak base and its conjugate acid ion.
.
.
.

.
What's the new salt-to-base ratio?
The 0.005 mol of HCl will convert 0.005 mol of base B to its conjugate acid ion BH⁺.
Initial:
;
.
After adding the HCl:
;
.
Assume that the volume is still 0.5 L:
.
.
What's will be the pH of the solution?
Apply the Henderson-Hasselbalch equation again:
![\displaystyle \text{pOH} = \text{pK}_b + \log{\frac{[\text{Salt}]}{[\text{Base}]}} = 4.64613 + \log{\frac{0.760}{1.04}} = 4.50991](https://tex.z-dn.net/?f=%5Cdisplaystyle%20%5Ctext%7BpOH%7D%20%3D%20%5Ctext%7BpK%7D_b%20%2B%20%5Clog%7B%5Cfrac%7B%5B%5Ctext%7BSalt%7D%5D%7D%7B%5B%5Ctext%7BBase%7D%5D%7D%7D%20%3D%204.64613%20%2B%20%5Clog%7B%5Cfrac%7B0.760%7D%7B1.04%7D%7D%20%3D%204.50991)
.
The final pH is slightly smaller than the initial pH. That's expected due to the hydrochloric acid. However, the change is small due to the nature of buffer solutions: adding a small amount of acid or base won't significantly impact the pH of the solution.