First we find for the wavelength of the photon released due
to change in energy level. We use the Rydberg equation:
1/ʎ = R [1/n1^2 – 1/n2^2]
where,
ʎ is the wavelength
R is the rydbergs constant = 1.097×10^7 m^-1
n1 is the 1st energy level = 1
n2 is the higher energy level = infinity, so 1/n2 = 0
Calculating for ʎ:
1/ʎ = 1.097×10^7 m^-1 * [1/1^2 – 0]
ʎ = 9.1158 x 10^-8 m
Then calculate the energy using Plancks equation:
E = hc/ʎ
where,
h is plancks constant = 6.626×10^−34 J s
c is speed of light = 3x10^8 m/s
E = (6.626×10^−34 J s * 3x10^8 m/s) / 9.1158 x 10^-8 m
E = 2.18 x 10^-18 J = 2.18 x 10^-21 kJ
This is still per atom, so multiply by Avogadros number =
6.022 x 10^23 atoms / mol:
E = (2.18 x 10^-21 kJ / atom) * (6.022 x 10^23 atoms /
mol)
E = 1312 kJ/mol
RMM of CaH2=20+(1x2)=22
Number of moles or formula units
=mass/RMM
=8.294/22
=0.377
<span>8.278 g/mL
The definition of density is mass per volume. So what you need to do is divide the known mass by the known volume. So
1.663 g / 0.2009 mL = 8.27775 g/mL
But you also have to keep track of significant figures. Since both 1.663 and 0.2009 have 4 significant figures each, you need to round the result to 4 significant figures. So
8.27775 g/mL = 8.278 g/mL</span>
1-It has to be 3 Fe and not Fe3.
2-The oxygens aren't balanced
Balanced equation:
3Fe+4H2O---->Fe3O4+4H2
Color they look the same hope this helps.
