Phenolphthalein is not a good indicator to use for a titration for a solution that has a ph of 6.0 at the equivalence point because the color change of the solution at this pH level is not sharp. It changes the color of the solution to pink starting from pH 8.3 to 10. A pH level lower than 8.3 would only show a colorless solution. Thus, you would not be able to distinguish whether the solution has reached its equivalence point at pH 6.0. It is best to use this indicator for a system that is using a strong base titrated with a weak acid.
Answer: 4.99×10²³ photons
Explanation: The energy of a photon is given as
E= hf
h= Planck constant = 6.626×10^-34Js
f= frequency = c/x
C= speed of light = 3×10^8 m/s
x= wavelength= 525nm= 525×10^-9
E= hc/x
E= 6.626×10^-34 × 3×10^8 m/s /( 525×10^-9)
E= 3.79×10^−19 J/ Photon
E= 3.79×10^−22KJ/Photon
189KJ/3.79×10^−22KJ/photon=
4.99×10²³photons.
Therefore the number of photons is
4.99×10²³photons.
Answer:
Each isotope of oxygen contains 8 protons, but differs in the number of neutrons. An isotope number is a shorthand representation of its mass. Because protons and neutrons are roughly equal in mass, an isotope's number is equal to the sum of its protons and neutrons.
Explanation:
Isotopes are atoms of the same element that have different numbers of neutrons but the same number of protons and electrons. The difference in the number of neutrons between the various isotopes of an element means that the various isotopes have different masses.
