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ch4aika [34]
3 years ago
14

Which weak acid would be best to use when preparing a buffer solution with a ph of 9.20?

Chemistry
2 answers:
Murrr4er [49]3 years ago
8 0

Answer:

The acid with about Ka=6.31x10^{-10}.

Explanation:

Hello,

By assuming that the dissociation of a weak acid is:

H^+X^-H^++X^-

From the following equation one computes pKa as long as the concentration of the conjugate base equals the concentration of the acid for this buffered solution:

pH=pKa+Log(\frac{[Conj.Base]}{[Acid]})\\pKa=pH-Log(1)\\pKa=pH=9.2\\Ka=10^{-9.2}\\Ka=6.31x10^{-10}

So the acid will be that with a Ka=6.31x10^{-10} or close since the possible answers are not shown.

Best regards.

wariber [46]3 years ago
6 0

Answer: -

6.31 x 10⁻¹⁰

Explanation: -

The equation for buffer pH

pH = pKa + log \frac{Conjugate Base}{Acid}

If [Conjugate base] = [Acid], then preparing a buffer is best.

Then pH = pKa

pKa = - log Ka

Ka = 10^{-9.2}

= 6.31 x 10⁻¹⁰

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zhenek [66]
Molarity can be defined as the number of moles of substance dissolved in 1 L of solution.
In the given question ,
number of LiOH moles - 1.495 mol
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molarity is calculated for 1 L = 1000 mL
In 750 mL - 1.495 mol of LiOH is dissolved
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4 0
3 years ago
how many moles of iron will be produced from 6.20 moles of carbon monoxide reacting with excess iron (III) oxide (FeO3) to produ
Gelneren [198K]

0.20 moles of iron will be formed in the reaction.

Explanation:

The balanced chemical equation for the reaction between iron (iii) oxide and carbon monoxide to form Fe is to be known first.

the balanced reaction is :

Fe2O3 + 3CO⇒ 2 Fe + 3 CO2

so from the data given the number of moles of carbon monoxide can be known:

3 moles of CO reacted with Fe2O3 to form 2 moles of iron in the reaction.

Number of moles of CO is 6.20 moles

11.6 gm of iron is formed

so the number of moles of iron formed is calculated as

n = mass of iron ÷ atomic weight of iron

  = 11.6 ÷ 55.84

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5 0
3 years ago
What is the molarity of formaldehyde in a solution containing 0.25 grams of formaldehyde per mL?
Vikentia [17]

Answer:

8.33mol/L

Explanation:

First, let us calculate the molar mass of of formaldehyde (CH2O). This is illustrated below:

Molar Mass of CH2O = 12 + (2x1) + 16 = 12 + 2 + 16 = 30g/mol

Mass of CH2O from the question = 0.25g

Number of mole CH2O =?

Number of mole = Mass /Molar Mass

Number of mole of CH2O = 0.25/30 = 8.33x10^-3mole

Now we can calculate the molarity of formaldehyde (CH2O) as follow:

Number of mole of CH2O = 8.33x10^-3mole

Volume = 1mL

Converting 1mL to L, we have:

1000mL = 1L

Therefore 1mL = 1/1000 = 1x10^-3L

Molarity =?

Molarity = mole /Volume

Molarity = 8.33x10^-3mole/1x10^-3L

Molarity = 8.33mol/L

Therefore, the molarity of formaldehyde (CH2O) is 8.33mol/L

3 0
3 years ago
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ruslelena [56]

Answer:I am not sure how

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Answer:

See explanation

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Four blue foam balls hanging from strings will represent the electrons around the nucleus.

Any model that corresponds to the description above is the correct answer.

7 0
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