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pshichka [43]
3 years ago
15

You have 50 ml of a complex mixture of weak acids that contains some HF (pKa = 3.18) and some HCN (pKa = 9.21). Which is larger,

[F-]/[HF] or [CN-]/[HCN]?
Chemistry
1 answer:
bonufazy [111]3 years ago
5 0

Answer:

\frac{[F^{-}]}{[HF]} is larger

Explanation:

pK_{a}=-logK_{a} , where K_{a} is the acid dissociation constant.

For a monoprotic acid e.g. HA, K_{a}=\frac{[H^{+}][A^{-}]}{[HA]} and \frac{[A^{-}]}{[HA]}=\frac{K_{a}}{[H^{+}]}

So, clearly, higher the K_{a} value , lower will the the pK_{a}

In this mixture, at equilibrium, [H^{+}] will be constant.

K_{a} of HF is grater than K_{a} of HCN

Hence, (\frac{F^{-}}{[HF]}=\frac{K_{a}(HF)}{[H^{+}]})>(\frac{CN^{-}}{[HCN]}=\frac{K_{a}(HCN)}{[H^{+}]})

So, \frac{[F^{-}]}{[HF]} is larger

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Hello! Here's the answer I was able to come up with:

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<em>Why do none of these diagrams show more than 8 dots?</em>

It is physically impossible for an atom to have more than 8 electrons in its valence layer, according to the Octet Rule.

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The dot diagram for each element represents the number of electrons each element will have in its outermost, or valence, shell. (2-8-8)

<em>The number of dots that hydrogen and helium have in their dot diagram is the same as the number of electrons shown for them on the Periodic Table. Why?</em>

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3 years ago
A reaction involves the parts of two compounds switching places to form two new compounds. What type of reaction is this?
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Double Displacement would be correct

5 0
3 years ago
Astroturf is a durable artificial surface used to cover athletic fields. A soccer field 0.06214- mile-long by 253 ft wide is cov
love history [14]

Answer:

The weight of the Astroturf is 179,684.31 Newtons.

Explanation:

Length of a soccer field = 0.06214 mile = 328.0992 feet

(1 mile = 5280 feet)

Breadth of a soccer field  = 253 feet

Length of a Astroturf which soccer field is to be covered, l = 328.0992 feet

Breadth of a Astroturf which soccer field is to be covered ,b = 253 feet

Thickness of a Astroturf with which soccer field is to be covered = h

h = ½ inch = 0.5 inch = 0.041665 feet

(1 inches = 0.08333 feet)

Volume of the Astroturf ,V= l × b × h

V=328.0992 ft\times 253 ft\times 0.041665 ft=3,458.574 ft^3

Mass of the Astroturf = m

Density of the Astroturf = d = 187 oz/ft^3

d=\frac{m}{V}

m=d\times V= 187 oz/ft^3\times 3,458.574 ft^3=646,753.35 oz

1 oz = 0.0283495 kg

m=646,743.35 oz=646,743.35\times 0.0283495 kg=18,335.13 kg

Weight of the Astroturf = W

W = mg

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The weight of the Astroturf is 179,684.31 Newtons.

8 0
3 years ago
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antiseptic1488 [7]

Answer: 480 kJ of energy is released when 3.5 mol of C_2H_4 reacts.

Explanation:

The balanced chemical reaction is:

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Thus it is given that the reaction is exothermic (heat energy is released) as enthalpy change for the reaction is negative.

1 mole of C_2H_4 on reacting gives = 137 kJ of energy

Thus 3.5 moles  of C_2H_4 on reacting gives = \frac{137}{1}\times 3.5=480 kJ of energy

Thus 480 kJ of energy is released when 3.5 mol of C_2H_4 reacts.

7 0
3 years ago
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