Calculate the energy(j) change associated with an electron transition from n=2 to n=5 in a bohr hydrogen atom. put answer in scientific notation.

4.58*10^(-19) J

Explanation:

Using the Rydberg's equation:

where

is  the wavelength of the photon;

R is the Rydberg's constant = 1.0974*10^7 m^(-1)

final level is 5 and initial level is 2.

Energy change is calculated with the next formula:

E = h*c/λ

where h is the Planck's constant = 6.626*10^(-34) J*s, and c is the speed of light = 299,792,458 m/s

E = 6.626*10^(-34)*299,792,458/-4.339*10^(-7)

E = 4.58*10^(-19) J

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.