Answer is 5 tho idk why the options so weird. anyways u have to use the periodic table, check for the element which has 8 protons. this will be oxygen.
to calculate electrons, take 16-8 hence u will have 8 electrons.
qn said u have net charge of 3+. this means that u have to minus 3 from the electrons
so 8-3 = 5
<span>D. not enough precipitation is the answer</span>
Answer:
They spread apart to fill the enclosed object. In other words they move freely...
hope this helped you
please mark as the brainliest(ㆁωㆁ)
Answer:
pH = 2.56
Explanation:
The Henderson-Hasselbalch equation relates the pH to the Ka and ratio of the conjugate acid-base pair as follows:
pH = pKa + log([A⁻]/[HA]) = -log(Ka) + log([A⁻]/[HA])
Substituting in the value gives:
pH = -log(1.77 x 10⁻⁴) + log((0.0065M) / (0.10M))
pH = 2.56
Answer:
2.51 Angstroms
Explanation:
For a particle in a one dimensional box, the energy level, En, is given by the expression:
En = n²π² ħ² / 2ma²
where n is the energy level, ħ² is Planck constant divided into 2π, m is the mass of the electron ( 9.1 x 10⁻³¹ Kg ), and a is the length of the one dimensional box.
We can calculate the change in energy, ΔE, from n = 2 to n= 3 since we know the wavelength of the transition ( ΔE = h c/λ ) and then substitute this value for the expresion of the ΔE for a particle in a box and solve for the length a.
λ = 207 nm x 1 x 10⁻⁹ m/nm = 2.07 x 10⁻⁷ m ( SI units )
ΔE = 6.626 x 10⁻³⁴ J·s x 3 x 10⁸ m/s / 2.07 x 10⁻⁷ m
ΔE = 9.60 x 10⁻¹⁹ J
ΔE(2⇒3) = ( 3 - 2 ) x π² x ( 6.626 x 10⁻³⁴ J·s / 2π )² / ( 2 x 9.1 x 10⁻³¹ Kg x a² )
9.60 x 10⁻¹⁹ J = π² x( 6.626 x 10⁻³⁴ J·s / 2π )² / ( 2 x 9.1 x 10⁻³¹ Kg x a² )
⇒ a = 2.51 x 10⁻¹⁰ m
Converting to Angstroms:
a = 2.51 x 10⁻¹⁰ m x 1 x 10¹⁰ Angstrom / m = 2.51 Angstroms
