Answer:
3.6
Explanation:
Step 1: Given data
- Concentration of formic acid: 0.03 M
- Concentration of formate ion: 0.02 M
- Acid dissociation constant (Ka): 1.8 × 10⁻⁴
Step 2: Calculate the pH
We have a buffer system formed by a weak acid (HCOOH) and its conjugate base (HCOO⁻). We can calculate the pH using the <em>Henderson-Hasselbach equation</em>.
![pH = pKa +log\frac{[base]}{[acid]} = -log 1.8 \times 10^{-4} + log \frac{0.02}{0.03} = 3.6](https://tex.z-dn.net/?f=pH%20%3D%20pKa%20%2Blog%5Cfrac%7B%5Bbase%5D%7D%7B%5Bacid%5D%7D%20%3D%20-log%201.8%20%5Ctimes%2010%5E%7B-4%7D%20%2B%20log%20%5Cfrac%7B0.02%7D%7B0.03%7D%20%3D%203.6)
Answer:
35.1 kJ/mol is the expected value for the heat of sublimation of acetic acid.
Explanation:
..[1]
Heat of vaporization of acetic acid = 
..[2]
Heat of fusion of acetic acid = 
Heat of sublimation of acetic acid = 
..[3]
[1] + [2] = [3] (Hess's law)
35.1 kJ/mol is the expected value for the heat of sublimation of acetic acid.
Answer:
Beta rays are electrons.
Explanation:
A neutron in the nucleus of a radioactive atom decays into a proton and an electron, which is emitted from the atom.
Answer:
OPTION C) All hydrogen ions and all hydroxide ions have reacted to produce water, and so neither ion remains free in solution.
Explanation:
The PH reading on the left axis of the graph shows a value of 7.
A value of 7 on the PH scale implies that equal number of hydrogen ions completely reacted with hydroxyl ions to produce water i.e there is no excess of hydrogen and hydroxyl ion remaining in solution.
For values greater than 7, a basic solution is formed and it signifies the presence of excess hydroxyl ion. If the value is less than 7, there is more hydrogen ions in the solution formed and it is said to be acidic.
At point 7, the hydrogen and hydroxyl ions are equal and completely neutralize out one another.
Note: The acid solution would require a base volume of 20mL to be completely neutralized according to the plot. If it is less, the PH shifts to the left and the solution becomes acidic. If it more, the solution becomes basic and the PH shifts rightwards.
