Answer: The energy of a photon with a wavelength of 820 nm is .
Explanation:
Given : Wavelength = 820 nm
Convert nm into meter as follows.
The relation between energy and wavelength is as follows.
where,
E = energy
h = Planck's constant =
c = speed of light =
= wavelength
Substitute the values into above formula as follows.
Thus, we can conclude that energy of a photon with a wavelength of 820 nm is .
Atomic mass Ca = 40.078 u.m.a
40.078 g --------------- 6.02x10²³ atoms
121 g ------------------- ??
121 x ( 6.02x10²³) / 40.078 =
7.28x10²⁵ / 40.078 = 1.81x10²⁴ atoms
The hydroxide ion concentration [OH-] in an aqueous solution is 6.66 x 10⁻⁹ M
Experimental measurements of the pKw of water at 25ºC yielded a result of 14.0. The same method used to determine the pKa of all other water-soluble compounds that can function as acids in aqueous solution can also be used to determine this value from the examination of thermodynamic or electrochemical data for these aqueous solutions.
Water has a pkw=14
So it can be represented as,
[H+] [OH-] = 1×10^-14
Given [H+] = 1. 5×10^−6
So, [OH-] = (1*10^-14) / ( 1.5*10^-6)
= 6.66 x 10⁻⁹ M
To know more about Aqueous Solution refer:
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Some examples of physical properties are:
color (intensive)
density (intensive)
volume (extensive)
mass (extensive)
boiling point (intensive): the temperature at which a substance boils.
melting point (intensive): the temperature at which a substance melts.