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4 years ago

A solution has [h3o+] = 4.2×10−5 m . use the ion product constant of water kw=[h3o+][oh−] to find the [oh−] of the solution.

1 answer:

4 0

Answer is: concentration of hydroxide ions is 2.38·10⁻¹⁰ M.
[H₃O⁺] = 4.2·10⁻⁵ M; equilibrium concentration of hydroxide ions.
The Kw (the ionic product for water) at 25°C is 1·10⁻¹⁴ mol²/dm⁶ or 1·10⁻¹⁴ M².
Kw = [H₃O⁺] · [OH⁻].
[OH⁻] = Kw ÷ [H₃O⁺].
[OH⁻] = 1·10⁻¹⁴ M² ÷ 4.2·10⁻⁵ M.
[OH⁻] = 2.38·10⁻¹⁰ M.

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Explanation:

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1s² < 2s² < 2p⁶ < 3s² < 3p⁶ < 4s² < 3d¹⁰ < 4p⁶ < 5s² < 4d¹⁰ < 5p⁶ < 6s² < 4f¹⁴ < 5d¹⁰ < 6p⁶ < 7s² < 5f¹⁴ < 6d¹⁰ < 7p⁶

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The maximum number of electrons in an s orbital is 2, so 2s⁴ is impossible, and this option is discarded.

Option C) 1s² 2s² 2p⁵

This is correct because the orbitals are filled in the correct increasing energy order, without jumping any one.

Option D) 1s² 2s² 2d⁶

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The complete question is as follows: Which statement describes the way in which energy moves between a system reacting substances in the surroundings.

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