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3 years ago

12

What are some possible explanations you think a researcher might find to explain why the fish are washing up on the shore of Lak

e Superior

1 answer:

8_murik_8 [283]3 years ago

5 0

Answer:

the temperature or weather ,

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What is the shape of sf6

zmey [24]

Answer:

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3 years ago

On the seashore pebbles that are rough and uneven become smooth and rounded explain how they become smooth and rounded

Andru [333]

The pebbles become smooth and even because of erosion. the waves from the sea rub against the pebbles this is erosion. x

7 0

3 years ago

Which equation is a decomposition reaction? Li2CO3 Right arrow. Li2O + CO2 Zn + HCl Right arrow. ZnCl2 + H2 Na2O + CO2 Right arr

Dmitrij [34]

Answer:

Li₂CO₃ ⇒ Li₂O + CO₂ is a decomposition reaction.

Explanation:

In a decomposition reaction, a single substance decomposes, producing two or more different substances. In other words, in this type of reaction two or more substances are formed from a compound. The atoms that form a compound separate to give the products according to the formula:

AB → A + B

It can occur spontaneously, or be aided by a catalyst, heat, or electrolysis.

In this case:

Li₂CO₃ ⇒ Li₂O + CO₂ It is a type of chemical reaction in which a single compound decomposes into two or more compounds. So it is a decomposition reaction.

3 0

4 years ago

How are binary ionic compounds and binary molecular compounds similar and 2 ways they are different?

saw5 [17]

Answer:

The elements that combine to form binary molecular compounds are both nonmetal atoms. This contrasts with ionic compounds, which were formed from a metal ion and a nonmetal ion. ... Prefixes are used in the names of binary molecular compounds to identify the number of atoms of each element.

5 0

3 years ago

A 1-liter solution contains 0.494 M hydrofluoric acid and 0.371 M potassium fluoride. Addition of 0.408 moles of hydrochloric ac

UkoKoshka [18]

Answer:

Option f: an addition of HCl will exceed the buffer capacity. The option d is also correct since it is a consequence of the option f.

Explanation:

The pH of the buffer solution before the addition of HCl is:

$pH = pKa + log(\frac{[KF]}{[HF]})$

$pH = -log(6.8 \cdot 10^{-4}) + log(\frac{0.371}{0.494}) = 3.04$

The hydrochloric acid added will react with the potassium fluoride as follows:

H₃O⁺(aq) + F⁻(aq) ⇄ HF(aq) + H₂O(l)

The number of moles (η) of potassium fluoride (KF) and the HF before the addition of HCl is:

$\eta_{KF}_{i} = C_{KF}*V = 0.371 M*1 L = 0.371 mol$

$\eta_{HF}_{i} = C_{HF}*V = 0.494 M*1 L = 0.494 moles$

The number of moles of the HCl added is 0.408 moles. Since the number of moles of HCl is bigger thant the number of moles of KF, the moles of HCl that remains after the reaction is:

$\eta_{HCl} = \eta_{HCl} - \eta_{KF}_{i} = 0.408 moles - 0.371 moles = 0.037 moles$

Hence, the KF is totally consumed after the reaction with HCl and thus, exceding the buffer capacity.

We can calculate the pH after the addition of HCl:

HF(aq) + H₂O(l) ⇄ F⁻(aq) + H₃O⁺(aq) (1)

The number of moles of HF after the reaction of KF with HCl is:

$\eta_{HF} = 0.494 moles + (0.408 moles - 0.371 moles) = 0.531 moles$

And the concentration of HF after the reaction of KF with HCl is is:

$C_{HF} = \frac{\eta_{HF}}{V} = \frac{0.531 moles}{1 L} = 0.531 moles/L$

Now, from the equilibrium of equation (1) we have:

$Ka = \frac{[H_{3}O^{+}][F^{-}]}{[HF]}$

$Ka = \frac{x^{2}}{0.531 - x}$ (2)

By solving equation (2) for x we have:

x = 0.0187

Finally, the pH after the addition of HCl is:

$pH = -log (H_{3}O^{+}) = -log (0.0187) = 1.73$

Therefore, the addition of HCl will exceed the buffer capacity and thus, lower the pH by several units. The correct option is f: an addition of HCl will exceed the buffer capacity. The option d is also correct since it is a consequence of the option f.

I hope it helps you!

8 0

4 years ago