This is the electron configuration of neptunium:
<span>Rn 5f4 6d1 7s2
</span>or, if you want to complicate:
<span>1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f4 6d1
</span>Since there are 93 electrons, they make up 5f4 altogether.
The atomic mass is measured in "atomic mass units" (amu). One mole of an element weighs the same atomic mass number, but in grams.
For example, carbon, C, has an atomic mass of 12.011 amu. One mole of carbon has a mass of 12.011 grams.
Answer:
268 nm
Explanation:
First' let's calculate the average bond energy:
(276 + 615)/2 = 445.5 kJ/mol
By Avogadro's number 1 mol = 6.02x10²³ molecule, then the energy necessary to break the amide bond in 1 molecule is:
E = 445.5/6.02x10²³ = 7.4x10⁻²² kJ = 7.4x10⁻¹⁹ J
So, the wavelength of light (λ) can be calculated by:
E= h*c/λ
Where h is the Planck's constant (6.626x10⁻³⁴ J.s), and c is the light speed (3.0x10⁸ m/s).
7.4x10⁻¹⁹ = 6.626x10⁻³⁴ * 3.0x10⁸/λ
λ = 2.68x10⁻⁷ m
λ = 268 nm
Because the density of the egg is higher than the density of tap water, so it sinks.
The question is incomplete, here is the complete question:
A chemist must prepare 550.0 mL of hydrochloric acid solution with a pH of 1.60 at
. He will do this in three steps: Fill a 550.0 mL volumetric flask about halfway with distilled water. Measure out a small volume of concentrated (8.0M) stock hydrochloric acid solution and add it to the flask. Fill the flask to the mark with distilled water. Calculate the volume of concentrated hydrochloric acid that the chemist must measure out in the second step. Round your answer to 2 significant digits.
<u>Answer:</u> The volume of concentrated hydrochloric acid solution is 1.7 mL.
<u>Explanation:</u>
To calculate the hydrogen ion concentration, we use the formula:
![pH=-\log [H^+]](https://tex.z-dn.net/?f=pH%3D-%5Clog%20%5BH%5E%2B%5D)
We are given:
pH = 1.60
Putting values in above equation, we get:
![1.60=-\log [H^+]](https://tex.z-dn.net/?f=1.60%3D-%5Clog%20%5BH%5E%2B%5D)
![[H^+]=antilog (-1.60)](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3Dantilog%20%28-1.60%29)
![[H^+]=0.0251M](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D0.0251M)
To calculate the volume of concentrated solution, we use the equation:

where,
= molarity and volume of concentrated acid solution
= molarity and volume of diluted acid solution
We are given:

Putting values in above equation, we get:

Hence, the volume of concentrated hydrochloric acid solution is 1.7 mL.