The correct answer is 2.73.
HF is a weak acid which partially dissociates to release H+ and F-
HF → H⁺ + F⁻
Initial 0.0050 0 0
Change -x +x +x
Equilibrium 0.0050–x +x +x
Solve by using the equilibrium expression: = [H⁺] [F⁻]/ [HF]
6 .8 x 10⁻⁴= x. x / 0.0050 –x
6 .8 x 10⁻⁴= x² /0.0050
x² = 6 .8 x 10⁻⁴ x 0.0050
x² = 3.4 x 10⁻⁶
x = 3.4 x 10⁻⁶
[H⁺] = 1.84 x 10⁻³
pH = - log [H⁺] = - log (1.84 x 10⁻³)
pH = 2.73
Answer is: a. Rubidium (Rb) is more reactive than strontium (Sr) because strontium atoms must lose more electrons.
The ionization energy (Ei) is the minimum amount of energy required to remove the valence electron, when element lose electrons, oxidation number of element grows (oxidation process).
Alkaline metals (group 1), in this example rubidium, have lowest ionizations energy and easy remove valence electrons (one electron), they are most reactive metals.
Earth alkaline metals (group 2), in this example strontium, have higher ionization energy than alkaline metals, because they have two valence electrons, they are less reactive.
Rubidium electron configuration: ₃₇Rb 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶5s¹; one valence electron is 5s¹ orbital.
Strontium electron configuration: ₃₈Sr 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶5s²; two valence electrons is 5s² orbital.
<span><span>one defintion is - to persude
another definiton is - to find guilty
</span></span>
Answer:
The purpose of a science experiment is to prove or deny a hypothesis. One's experiment is not a failure if the results do not match the hypothesis. When the data does not support the hypothesis, record it as though it did.