Answer:
0.009
Explanation:
Molarity, a measure of molar concentration of a substance is calculated thus;
Molarity = number of moles รท volume
According to the provided information, mass of KCl = 0.47g, volume of water = 700ml
Using mole = mass/molar mass
Molar Mass of KCl = 39.10 + 35.453
= 74.553g/mol
Mole = 0.47/74.55
Mole = 0.0063mol
Volume of water = 700ml = 700/1000 = 0.7L
Molarity = 0.006/0.7
Molarity = 0.00857
The value of molarity rounded to three decimal places (3 d.p) = 0.009
The blue colour of the sky results from the scattering of sunlight by air molecules. Blue light has a frequency if about 7.5*10^14Hz
Calculate the energy of a mole of photon associated with this frequency
Answer: The energy of a mole of photon associated with this frequency is [tex]49.5\times 10^{-20}J[/tex]
Explanation:
The energy and frequency are related by :
[tex]E=N\times h\times \nu[/tex]
E = energy of photon
N = number of moles = 1
h = planks constant = [tex]6.6\times 10^{-34}Js[/tex]
[tex]\nu[/tex] = frequency = [tex]7.5\times 10^{14}Hz[/tex]
[tex]E=1\times 6.6\times 10^{-34}Js\times 7.5\times 10^{14}s^{-1}=49.5\times 10^{-20}J[/tex]
The energy of a mole of photon associated with this frequency is [tex]49.5\times 10^{-20}J[/tex]