9.01 × 10⁻²⁶ J
<h3>Explanation</h3>
ΔE = h · f
Where
- ΔE the change in energy,
- h the planck's constant, and
- f frequency of the emission.
However, only λ is given.
f = c / λ
Where
- f frequency of the emission,
- λ wavelength of the emission, and
- c the speed of light.
For this emission:
f = 2.998 × 10⁸ / 2.21 = 1.36 × 10⁸ s⁻¹.
ΔE = h · f = 6.626 × 10⁻³⁴ × 1.36 × 10⁸ = 9.01 × 10⁻²⁶ J
Answer:
1 = strontium
2 = technetium
3 = silver
Explanation:
Strontium is present in 2 group of periodic table. It is alkaline earth metal. It is most reactive element and can not found free in nature. it is insoluble in water but react with water and form strontium hydroxide and hydrogen gas is also produced. It is radioactive element.
It is similar to the calcium and can incorporated into bones. The food rich with strontium is used to avoid the osteoporosis. It is found in leafy vegetables, grains, sea foods etc.
In given series strontium is highest in reactivity then technetium, while the technetium is more reactive than silver. The silver is less reactive as compared to both given elements.
The pH of the solution of the given acid is 3.099
Let HX be the weak acid:
HX ⇌ 
+ 
For which:
= [ ][ ] / [HX]
If lies in the range 
we can assume that the equilibrium concentrations used in the expression are a good enough approximation to the initial concentrations.
Rearranging and taking negative logs of both sides gives:
pH = ![\frac{1}{2} [pK_{a} - loga]](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B2%7D%20%5BpK_%7Ba%7D%20-%20loga%5D)
a is the concentration of the acid.
= -log (2×
) = 5.69
pH = ![\frac{1}{2} [5.69- (-0.508)]](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B2%7D%20%5B5.69-%20%28-0.508%29%5D)
pH = 3.099
Learn more about pH of acid here;
brainly.com/question/13043236
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It depends on what the remains are. If you are looking for a word, it could either be fossils or if it is something that has preserved the soft tissue it can be described as mummified.
Answer: The octet rule is a chemical rule of thumb that reflects the observation that main group elements tend to bond in such a way that each atom has eight electrons in its valence shell, giving it the same electronic configuration as a noble gas.
Explanation:
