multiply by 100.4.36×10-5cm
Answer:
Mole fraction for C₂₂H₁₉Cl₂NO₃ = 0.0086
Explanation:
Mole fraction remains a sort of concentration. It indicates:
moles of solute / (moles of solute + moles of solvent)
Moles of solute / Total moles.
Solute: Cypermethrin → C₂₂H₁₉Cl₂NO₃
Solvent: Water (PM = 18g/mol)
We calculate moles from solvent: 1000g /18 g/mol = 55.5 moles
We calculate PM for C₂₂H₁₉Cl₂NO₃
12g/mol . 22 + 1g/mol . 19 + 35.45 g/mol . 2+ 14g/mol + 16g/mol . 3 = 416 g/m
Moles of solute: 200 g / 416g/mol = 0.481 moles
Total moles: 0.481 + 55.5 = 55.98 moles
Mole fraction for C₂₂H₁₉Cl₂NO₃ = 0.481 moles / 55.98 moles = 0.0086
Answer:
4.1x10⁻⁵
Explanation:
The dissociation of an acid is a reversible reaction, and, because of that, it has an equilibrium constant, Ka. For a generic acid (HA), the dissociation happens by:
HA ⇄ H⁺ + A⁻
So, if x moles of the acid dissociates, x moles of H⁺ and x moles of A⁻ is formed. the percent of dissociation of the acid is:
% = (dissociated/total)*100%
4.4% = (x/[HA])*100%
But x = [A⁻], so:
[A⁻]/[HA] = 0.044
The pH of the acid can be calcualted by the Handersson-Halsebach equation:
pH = pKa + log[A⁻]/[HA]
3.03 = pKa + log 0.044
pKa = 3.03 - log 0.044
pKa = 4.39
pKa = -logKa
logKa = -pKa
Ka = 
Ka = 
Ka = 4.1x10⁻⁵
It is a physical change because only the states as being changes, not the actual bonds in the compound.
Answer:
Approximately
.
Explanation:
The Lyman Series of a hydrogen atom are due to electron transitions from energy levels
to the ground state where
. In this case, the electron responsible for the line started at
and transitioned to
A hydrogen atom contains only one electron. As a result, Bohr Model provides a good estimate of that electron's energy at different levels.
In Bohr's Model, the equation for an electron at energy level
(
(note the negative sign in front of the fraction,)
where
is a constant.
is the atomic number of that atom.
for hydrogen.
is the energy level of that electron.
The electron that produced the
line was initially at the
.
The electron would then transit to energy level
. Its energy would become:
.
The energy change would be equal to
.
That would be the energy of a photon in that
spectrum line. Planck constant
relates the frequency of a photon to its energy:
, where
is the energy of the photon.
is the Planck constant.
is the frequency of that photon.
In this case,
. Hence,
.
Note that
.