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GREYUIT [131]
3 years ago
11

In a 0.730 M solution, a weak acid is 12.5% dissociated. Calculate Ka of the acid.

Chemistry
1 answer:
Mamont248 [21]3 years ago
5 0

Answer:

Approximately 1.30 \times 10^{-2}, assuming that this acid is monoprotic.

Explanation:

Assume that this acid is monoprotic. Let \rm HA denote this acid.

\rm HA \rightleftharpoons H^{+} + A^{-}.

Initial concentration of \rm HA without any dissociation:

[{\rm HA}] = 0.730\; \rm mol \cdot L^{-1}.

After 12.5\% of that was dissociated, the concentration of both \rm H^{+} and \rm A^{-} (conjugate base of this acid) would become:

12.5\% \times 0.730\; \rm mol \cdot L^{-1} = 0.09125\; \rm mol \cdot L^{-1}.

Concentration of \rm HA in the solution after dissociation:

(1 - 12.5\%) \times 0.730\; \rm mol \cdot L^{-1} = 0.63875\; \rm mol\cdot L^{-1}.

Let [{\rm HA}], [{\rm H}^{+}], and [{\rm A}^{-}] denote the concentration (in \rm mol \cdot L^{-1} or \rm M) of the corresponding species at equilibrium. Calculate the acid dissociation constant K_{\rm a} for \rm HA, under the assumption that this acid is monoprotic:

\begin{aligned}K_{\rm a} &= \frac{[{\rm H}^{+}] \cdot [{\rm A}^{-}]}{[{\rm HA}]} \\ &= \frac{(0.09125\; \rm mol \cdot L^{-1}) \times (0.09125\; \rm mol \cdot L^{-1})}{0.63875\; \rm mol \cdot L^{-1}}\\[0.5em]&\approx 1.30 \times 10^{-2} \end{aligned}.

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What is the identity of the element which had the following electron configuration? 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^5 ​
kati45 [8]

Answer:

The element with electron configuration 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^5 ​ is manganese (25Mn).

Explanation:

Step 1: Data given

The element with electron configuration 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^5 ​

has 25 electrons.

This element has 2 electrons on the first shell, 8 electrons on the second shell, 13 electrons on the third shell and 2 electrons on the outer shell (valence electrons).

This means this element is part of group VII.

The element with 25 electrons, we can find on the periodic table, with atomic number 25.

The element with electron configuration 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^5 ​ is manganese (25Mn).

5 0
3 years ago
Which type of bonding involves the complete transfer of a valence electron from a less electronegative atom to a more electroneg
Ivan

Answer:

Ionic or electrovalent bonds

Explanation:

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Electronegativity is the property that combines the ability of an atom to gain or lose electrons. It is expressed as the tendency with which atoms of elements attracts valence electrons in a chemical bond.

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3 years ago
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Answer:

i think several days of gray skies

Explanation:

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3 years ago
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Iron(II) sulfate, an iron supplement , FeSO4 Express your answer to four significant figures and include the appropriate units.
strojnjashka [21]

Answer:

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Explanation:

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The atomic masses are given as follows;

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Molar mass = ( 1 * Fe) + (1 * S) + (4 * O)

Molar mass = (1 * 55.854 ) + ( 1 * 32.065) + (4 * 15.999)

Molar mass = 151.915  g/mol

In four significant figures;

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3 years ago
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group NO3 comes from HNO3...and oxidation number of whole acid group is always on minus and equal to the amount of hydrogen atoms in this acid... so oxidation number of NO3 = -1

we have 2 NO3 groups so 2*(-1) = -2 and that is the reason why oxidation number of Fe in this formula must be +2... because sum of all elements always gives 0!

Now we could count of oxidation number for nitrogen... we write HNO3 and start counting from right to left:
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so nitrogen must have +5 oxidation number... because sum all in formula must be 0.


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2 years ago
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