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3 years ago

The ka of hf is 6.8 x 10-4. what is the ph of a 0.35 m solution of hf?

1 answer:

6 0

When the reaction equation is:

HF ↔ H+ + F-

and when the Ka expression
= concentration of products/concentration of reactions

so, Ka = [H+][F-]/[HF]

when we assume:

[H+] = [F-] = X

and [HF] = 0.35 - X

So, by substitution:

6.8 x 10^-4 = X^2 / (0.35 - X) by solving for X

∴ X = 0.015 M

∴[H+] = X = 0.015

when PH = -㏒[H+]

∴PH = -㏒0.015

= 1.8

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frozen [14]

Answer: 75 grams sample of chemical X should contain 21.43 grams of carbon

Explanation: The law of definite proportion states that a given chemical compound always contains its component elements in fixed ratio.

From the question, chemical X contains 5.0 grams of oxygen, 10.0 grams of carbon, and 20.0 grams of nitrogen.

Sum up the masses

5.0g + 10.0g + 20.0g = 35.0g

This means, 10.0 grams of carbon are present in 35.0 grams of chemical X.

Now, to the determine the mass of carbon that 75 gram sample of chemical X should contain,

According to the law of definite proportion, the component elements of a given chemical compound are in fixed ratio. Therefore,

If 35.0g of chemical X contains 10.0g of carbon

Then, 75 g of chemical X will contain

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3 years ago

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What is the mass of 7.1 x 1021 molecules of glucose?

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Answer:

7249.1

Explanation:

Multiply 7.1x1021= 7249.1

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3 years ago

What is going on inside atoms of a metal when a metallic salt of that metal is dissolved in water and then placed in a hot flame

dangina [55]

In flame tests salts that are dissolved in water are evaporated using a hot flame. In the flame the metal atoms become excited and produce their characteristic spectrum of light. Hope this answers the question. Have a nice day. Feel free to ask more questions.

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3 years ago

In the compound h2s hydrogen has an oxidation number of 1+ and sulfur has an oxidation number of

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Oxidation number is defined as the total number of electrons that are gained or lost by the atom to form a chemical bond.
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the sum of the oxidation numbers of the individual elements should add up to the oxidation number of the compound.

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4 years ago

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Which one of the following statements best describes a solution with a pH of 3?

zalisa [80]

Statement D is the correct option as the solution will have pH of 3. It has an H3O+ ion concentration of 1 × $10^{-3}$ mol/L and is acidic.

Explanation:

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pH of the solution is calculated as:

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