<span>When pKas of polyprotic intermediates have a difference of 2 or more you just average them using the equation: pH = (pKa2 + pKa3) / 2 </span>
<span>pKa2 = -log(Ka2) ; pKa3 = -log(Ka3) </span>
<span>so, for this problem, REGARDLESS OF THE CONCENTRATION GIVEN, the answer is: </span>
<span>pH = (7.2076+12.3767) / 2 </span>
<span>pH = 9.79</span>
Answer:
- <u>The pointer will not be lined up with the zero mark; it will be above the zero mark.</u>
Explanation:
Althoug the list of statements is not provided, you can assure that the pointer will not be lined up with the zero mark, but above the zero mark.
A <em>triple beam balance</em> is very precise instrument, of common use in most labs, used to measure masses. It has three beams. Each beam works for different precisions and mass increments. One beam measures 1 g increments, other beam measures 10 g increments, and the other one 100 g increments.
If you place a mass of 250 grams on the measurement tray, then the weight will be balanced in the beams with 200 grams in the beam that reads increments of 100 g and 50 grams in the beam that reads increments of 10 g. When this is the situation, the weight is completely balanced, and the pointer will be lined up with the zero mark. But this is not the case.
When the rider on the 500 gram beam is set to the 200 gram mark, and the other riders are set to 0 grams, the weight of the mass (250 g) on the tray is greater than the force exerted by the rider on the beam (200 g) and so the tray will be below the level of balance, and the beam will be above the level of balance. The level of balance is indicated when the pointer is lined up with the zero mark.
Of the following, which is most likely to result after a farmer sprays his crops with pesticides?D. A neighbor’s well tests positive for pesticides.
Carbon dioxide is a colorless, odorless gas. Why is it considered a pollutant?
A. It gets into natural waters and kills fish.
Answer : The volume in mL of the sodium carbonate stock solution is 364 mL.
Explanation :
According to dilution law:
where,
= molarity of aqueous sodium carbonate
= molarity of aqueous sodium carbonate stock solution
= volume of aqueous sodium carbonate
= volume of aqueous sodium carbonate stock solution
Given:
= 1.00 M
= 1.58 M
= 575 mL
= ?
Now put all the given values in the above formula, we get:
Therefore, the volume in mL of the sodium carbonate stock solution is 364 mL.
Answer:
The correct option is C) The number of protons is equal to the number of electrons.
Explanation:
Atoms are made up of particles called protons, neutrons, and electrons. Protons and neutrons are in the center of the atom and form the nucleus, while electrons surround the nucleus. Electrons have a negative charge. The charge of the protons is positive and finally, the neutrons have no charge.
If the atom has no charge, this means that the total charge of the atomic nucleus, which is positive due to the presence of the protons, is equal to the negative charge of the electrons, so that it cancels out.
So, <u><em>the correct option is C) The number of protons is equal to the number of electrons.</em></u>
