Answer:
A
Explanation:
To calculate questions like this, you need to make use of the equation below:
E = hν
E is the energy, h is Planck's constant, and ν is the frequency.
Also, another important formula you need for this question is the following:
ν = c / λ
ν is the frequency, c is the speed of light, and λ is the wavelength.
Therefore, E = hν = hc/λ.
Also remember to convert nm wavelength to meters.
To answer the question, E = hc/λ = ((6.626*10^-34 J•s)(3*10^8 m/s))/(4.45*10-7 m) = 4.42 • 10^-19 J = A
In deserts, wind often causes weathering by blowing sand and other material against cliffs and large rocks. This wears them down and creates more bits of sand and dust. Over time, the rock is scraped and polished away. ... When a gust of wind blows, it picks up sand and other bits of material.
Answer : The value of 
for the reaction is +571.6 kJ/mole.
Explanation :
According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
The given chemical reaction is,
Now we have to determine the value of for the following reaction i.e,
According to the Hess’s law, if we reverse the reaction then the sign of change.
So, the value 
for the reaction will be:
Hence, the value of for the reaction is +571.6 kJ/mole.
For the given molecule, we are asked to give-
- The electron configuration of an isolated B atom
- The electron configuration of an isolated F atom
- Hybrid orbitals should be constructed on the B atom to make the B–F bonds in Boron tri flouride
- valence orbitals, if any, remain unhybridized on the B atom.
- The electron configuration of an isolated B atom:
as atomic number of B is 5
electronic configuration will be [He] 2s² 2p¹
- The electron configuration of an isolated F atom:
as atomic number of F is 9
electronic configuration will be [He] 2s² 2p5
- Hybrid orbitals should be constructed on the B atom to make the B–F bonds in Boron tri flouride will be sp2.
as the one s and two of p orbital from the valance shell will hybridised to make 3 hybrid orbital of B resulting in 3 B-F bonds.
- valence orbitals, if any, remain unhybridized on the B atom will be 1
To know more about hybrisisation:
brainly.com/question/23038117
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