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WITCHER [35]
2 years ago
5

What is the pH of a 0.28 M solution of ascorbic acid (Vitamin C)? (The values for Ka1 and Ka2 for ascorbic acid are 8.0×10−5 and

1.6×10−12, respectively.) What is the of a 0.28 solution of ascorbic acid (Vitamin C)? (The values for and for ascorbic acid are and , respectively.) 2.04 2.32 2.82 4.65 6.17
Chemistry
1 answer:
Tomtit [17]2 years ago
5 0

Answer:

pH = 2.32

Explanation:

H2A + H2O -------> H3O+ + HA-    

Ka2 is very less so i am not considering that dissociation.

now Ka = 8.0×10−5

            = [H3O+] [HA-] / [H2A]

lets concentration of H3O+ = X then above equation will be

8.0×10−5 = [X] [X] / [0.28 -X]

8.0×10−5 = X2 /  [0.28 -X]

X2 + 8.0×10−5 X - 2.24 x 10−5

solve the quardratic equation

X =0.004693 M

pH = -log[H+}

    = -log [0.004693]

    = 2.3285

    ≅2.32

pH = 2.32

You might be interested in
A 5.91 g unknown sample analyzed by elemental analysis revealed a composition of 37.51 % C. In addition, it was determined that
SSSSS [86.1K]

Answer:

  • C₆H₈O₇

Explanation:

<u>1) Calculate the mass of carbon (C)</u>

  • mass of C = % of C × mass of sample / 100

  • mass of C = 37.51% × 5.91 g / 100 = 2.21 g

<u>2) Calculate the number of moles of C</u>

  • number of moles = mass in grams / molar mass

  • number of moles of C = 2.21 g / 12.01 g/mol = 0.184 moles

<u>3) Calculate the number of moles of hydrogen atoms, H:</u>

  • number of moles = number of atoms / Avogadro's number

  • number of moles of H = 1.4830 × 10²³ / 6.022 × 10²³ = 0.24626 moles

<u>4) Calculate the number of moles of oxygen atoms, O:</u>

  • number of moles = number of atoms / Avogadro's number

  • number of moles of O = 1.2966 × 10²³ / 6.022 × 10²³ = 0.21531 moles

<u>5) Find the </u><u>mole ratios</u><u>:</u>

Summary of moles:

  • C: 0.184 mol
  • H: 0.24626 mol
  • O: 0.21531 mol

Divide every amount by the smallest number, which is 0.184:

  • C: 0.184 / 0.184 = 1
  • H: 0.24626 / 0.184 = 1.34
  • O: 0.21531 / 0.184 = 1.17

Multiply by 3 to round to integer numbers:

  • C:  1 × 3 = 3
  • H: 1.34 × 3 = 4.02 ≈ 4
  • O: 1.17 × 3 = 3.51

Multiply by 2 to round to integer numbers:

  • C:  3 × 2 = 6
  • H: 4 × 2 = 8
  • O: 3.51 × 2 ≈ 7

Use the mole ratios as superscripts to write the empirical formula

  • C₆H₈O₇ ← answer

Just as a reference, you can search in internet and find that one compound with that empirical formula is citric acid.

7 0
2 years ago
eleanor purchased $2568 worth of stock and paid her broker a 0.5% fee. She sold the stock when the stock price increased to 3928
Mrrafil [7]

Answer: $1338.16

Explanation: Total cost of stock= $2568

Total cost of stock including the brokerage =2568+\frac{0.5}{100}\times {2568}=2580.84$

Selling price of stock = $3928

Selling price of stock including trading fee=($3928-$7)=$3919

Net Proceeds = Net selling price of stock - Cost Price of stock

Net Proceeds = ($3919 - $2580.84) = $1338.16


5 0
2 years ago
How much salt (NaCl) is carried by a river flowing at 30.0 m3/s and containing 50.0 mg/L of salt? Give your answer in kg/day.
ser-zykov [4K]

Answer:

129,600kg/day

Explanation:

The river is flowing at 30.0m^{3}/s

1m^{3}/s = 1000L

Multiply by 1000 to convert  to L/s

flowrate of river = 30*1000 =30,000L/s

Convert L/s to litre per day by multiplying by 24*60*60

flowrate of river = 30,000 * 24*60*60 L/day

                     = 2,592,000,000L/day

if the river contains 50mg of salt  in 1L of solution

lets find how many mg of salt (X) is contained in 2,592,000,000L/day

X= \frac{ 2,592,000,000*50}{1}

X= 129,600,000,000 mg/day

convert this value to kg/day by multiply by 10^{-6}

X= 129,600kg/day

7 0
2 years ago
How many liters of a 0.0550 M NaF solution contain 0.163 moles of NaF?
Kobotan [32]

Answer : The volume of solution will be 2.96 liters.

Explanation :

Molarity : It is defined as the number of moles of solute present in one liter of volume of solution.

Formula used :

\text{Molarity}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}

In this question, the solute is NaF.

Now put all the given values in this formula, we get:

0.0550M=\frac{0.163mole}{\text{Volume of solution (in L)}}

\text{Volume of solution (in L)}=\frac{0.163mole}{0.0550M}

\text{Volume of solution (in L)}=2.96L

Therefore, the volume of solution will be 2.96 liters.

3 0
2 years ago
A solution is prepared by dissolving 10.0 g of NaBr and 10.0 g of Na2SO4 in water to make a 100.0 mL solution. This solution is
Colt1911 [192]

Answer:

M_{Na^+}=1.36M

M_{Br^-}=1.58M

Explanation:

Hello,

At first, it turns out convenient to compute the total moles of sodium that will be dissolved into the solution by considering the added amounts of sodium bromide and sodium sulfate:

n_{Na^+}=n_{Na^+,NaBr}+n_{Na^+,Na_2SO_4}\\n_{Na^+,NaBr}=10.0gNaBr*\frac{1molNaBr}{103gNaBr}*\frac{1molNa^+}{1molNaBr}=0.0971molNa^+\\n_{Na^+,Na_2SO_4}=10.0gNa_2SO_4*\frac{1molNa_2SO_4}{142gNa_2SO_4}*\frac{2molNa^+}{1molNa_2SO_4} =0.141molNa^+\\n_{Na^+}=0.0971molNa^++0.141molNa^+\\n_{Na^+}=0.238molNa^+

Once we've got the moles we compute the final volume via:

V=100.0mL+75.0mL=175.0mL*\frac{1L}{1000mL}=0.1750L

Thus, the molarity of the sodium atoms turn out into:

M_{Na^+}=\frac{0.238mol}{0.1750L} =1.36M

Now, we perform the same procedure but now for the bromide ions:

n_{Br^-}=n_{Br^-,NaBr}+n_{Br^-,AlBr_3}\\n_{Br^-,NaBr}=10.0gNaBr*\frac{1molNaBr}{103gNaBr}*\frac{1molBr^-}{1molNaBr}=0.0971molBr^-\\n_{Br^-,AlBr_3}=0.0750L*0.800\frac{molAlBr_3}{L} *\frac{3molBr^-}{1molAlBr_3}=0.180molBr^- \\n_{Br^-}=0.0971molBr^-+0.180molBr^-\\n_{Br^-}=0.277molBr^-

Finally, its molarity results:

M_{Br^-}=\frac{0.277molBr^-}{0.1750L}=1.58M

Best regards.

7 0
2 years ago
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