Many of the atomic masses listed on the periodic table are decimal values because it's the weighted average mass of all of the isotopes of that element.
Answer:
(E) 90°
Explanation:
An octahedral molecule has a central atom surrounded by six(6) bonding atoms and no lone pair of electron,example is Sulphur hexafluoride (SF6).the bond anle is 90°
HCOOH + H2O <---> HCOO- + H3O+
<span>Ka = 1.8 X 10^-4 = [HCOO-][H3O+] / [HCOOH] </span>
<span>In the solution, [HCOO-] = [H3O+] = x </span>
<span>Quite properly, [HCOOH] = (2.30 X 10^-3 - x). </span>
<span>Since the formic acid solution is pretty dilute, and since Ka is sort of small, we can initially assume that x will be small compared to 2.3 X 10^-3, and so we can ignore it. If we do that, then, </span>
<span>Ka = x^2 / 2.30X10^-3 = 1.80 X 10^-4 </span>
<span>x = 6.4 X 10^-4 = [H3O+] </span>
<span>pH = 3.19 </span>
<span>Now, quite properly, our assumption that x would be small compared to 2.3 X 10^-3 is incorrect, and we really cannot ignore x in that expression. So, we should go back to the original expression for Ka: </span>
<span>Ka = x^2 / (2.30 X 10^-3 - x) = 1.80 X 10^-4 </span>
<span>Quite properly, you should rearrange this into a quadratic form and use the quadratic equation to solve for x. Once you've done that, x = [H3O+], and pH = - log (x).</span>
Emitting a positron (e+) means the atomic number of product nuclei decreased by one, with the same mass number.
Atomic number 20 is of Calcium, so 
.
So, 44Ca₂₂
<h3>What is nuclear decay?</h3>
The process through which an unstable atomic nucleus loses energy through radiation is known as radioactive decay, also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration. A substance that has unstable nuclei is regarded as radioactive. Alpha decay, beta decay, and gamma decay are three of the most frequent kinds of decay, and they all entail the emission of one or more particles. Beta decay is governed by the weak force, whereas the nuclear force and electromagnetism are in charge of the other two. Electron capture is a fourth type of common decay in which an unstable nucleus seizes an inner electron from one of the electron shells.
Discrete X-rays are released from the transitions as a result of the loss of that electron from the shell, which causes a cascade of other electrons to fall into the lower shell. Iodine-125, which is frequently utilized in medical contexts, is an example.
To learn more about nuclear decay, visit;
brainly.com/question/12868773
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Answer:
The wind energy and solar energy have their own benefits when producing electricity but one of their major drawbacks is that both these energy form depends on the environmental conditions and cannot be stored.
On the other hand, in hydroelectric pumped storage, water is stored in the form of gravitational potential energy. If not enough water is there to produce electricity, then this stored water can be run over turbines to produce electricity. Hence, this is one benefit of hydroelectric pumped storage over wind and solar energy.
