Answer:
<h3>a. noble gases</h3>
Explanation:
Groups are numbered 1–18 from left to right. The elements in group 1 are known as the alkali metals; those in group 2 are the alkaline earth metals; those in 15 are the pnictogens; those in 16 are the chalcogens; those in 17 are the halogens; and those in 18 are the noble gases.
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The answer is pH = 4.6. Methyl orange would turn yellow if the pH is above 4 and methyl red turns red when the pH level is below 5. So, it should be PH = 4.6<span>
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the universe formed through the big bang explosion, all of the elements on Earth have been cooked for billions of years in stars and then released in the universe through super- nova explosions.
Answer:
TBH Ion know the Answer Buttttt Good Luck :)
Explanation:
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