Answer:
the wavelength, in nm, of the photon is 487.5 nm
Explanation:
Given:
n = 4 (excited)
n = 2 (relaxes)
Question: Calculate the wavelength, in nm, λ = ?
First, it is important to calculate the energy of the electron when it excited and then when it relaxes.
(excited)
(relaxes)
The change of energy
ΔE = E₁ - E₂=-0.85 - (-3.4) = 2.55 eV = 4.08x10⁻¹⁹J
For a photon, the wavelength emitted
Here
h = Planck's constant = 6.63x10⁻³⁴J s
c = speed of light = 3x10⁸m/s
Substituting values:
GDP measures the value of goods and services produced within a country's borders, by citizens and non-citizens alike. GNP measures the value of goods and services produced by only a country's citizens but both domestically and abroad. GDP is the most commonly used by global economies.
Answer:
Populations have genetic variation.
The environment changes.
Organisms must have specific traits in order to survive and reproduce.
Explanation:
Natural selection is a phenomenon whereby organisms better adapted to their environment are able to survive due to this phenotypic capability.
- Natural selection provides an advantage during an adverse condition for organisms that have a rich genetic variation in their population.
- Also, environmental changes induces natural selection whereby organisms must adapt to changes around.
- For organisms to survive, they must have specific traits that gives them a competitive reproductive advantage.
The combustion reaction is as expressed,
CxHy + O2 --> CO2 + H2O
The mass fraction of carbon in CO2 is 3/11. Hence,
mass of C in CO2 = (3.14 g)(3/11) = 0.86 g C.
Given that we have 1 g of the hydrocarbon, the mass of H is equal to 0.14 g.
moles of C = 0.86 g C / 12 g = 0.0713
moles of H = 0.14 g H / 1 g = 0.14
The empirical formula for the hydrocarbon is therefore, CH₂.
Answer:
92.6 kJ.
Explanation:
<em>∵ ΔG°rxn = - nFE°cell,</em>
Where, ΔG°rxn is the standard free energy change (J).
n is the no. of electrons in the reaction (n =2).
F is Faraday constant (C/mol) (F = 96500 C/mol).
E°cell is the standard cell potential (E°cell = - 0.48 V).
<em>∴ ΔG°rxn = - nFE°cell </em>= - (2)(96500 C/mol)(- 0.48 V) = <em>92640 J = 92.64 kJ.</em>
