An atom that has 13 protons and 15 neutrons is isotope of Aluminium (answer C)
<u><em>Explanation</em></u>
- Isotope is a form of the same element with the equal number of protons but difference number of neutrons in their nuclei.
- In other words isotope has the same atomic number but different mass number.
- Atomic number of a element is determined by number of protons of an element.
- from the periodic table Aluminum in atomic number 13 therefore it has 13 protons <em>therefore an atom that has 13 protons and 15 neutrons is a isotope of Aluminium. </em>
Answer: the pH of the solution is 4.52
Explanation:
Consider the weak acid as Ha, it is dissociated as expressed below
HA H⁺ + A⁻
the Henderson -Haselbach equation can be expressed as;
pH = pKa + log( [A⁻] / [HA])
the weak acid is dissociated into H⁺ and A⁻ ions in the solution.
now the conjugate base of the weak acid HA is
HA(aq) {weak acid} H⁺(aq) + A⁻(aq) {conjugate base}
so now we calculate the value of Kₐ as well as pH value by substituting the values of the concentrations into the equation;
pKₐ = -logKₐ
pKₐ = -log ( 7.4×10⁻⁵ )
pKₐ = 4.13
now thw pH is
pH = pKₐ + log( [A⁻] / [HA])
pH = 4.13 + log( [0.540] / [0.220])
pH = 4.13 + 0.3899
pH = 4.5199 = 4.52
Therefore the pH of the solution is 4.52
Your answer would be 58.12g/mol ;)
Hey I tried but could not find your answer, but maybe you could try to calculate the average of bpts of the different elements in the compound to find the boiling point. And when you know the bpt, you can find out whether it is a liquid or gas. But after searching a lot, I found it was a solid. Good luck!
The elements in each group have the same number of electrons in the outer orbital. Or also called valence electrons. Khan academy has a great video online explaining why this happens. (It only happens for main group elements). Here is a link (sorry you can’t click it in Brainly) https://www.khanacademy.org/science/chemistry/periodic-table/copy-of-periodic-table-of-elements/v/periodic-table-valence-electrons. Feel free to message me for a better explanation, I would explain now but I’m not sure how much you know about this. If you know how to write an electron configuration you can see how all the electron configurations for the same group (not the transitional metals only the main groups) have the same number of valence electrons. I hope that helped, sorry I was vague about the explanation :)
