What is the role of blood in the transportation of materials throughout the body

(3) A 10.00-mL sample of 0.1000 M KH2PO4 was titrated with 0.1000 M HCl Ka for phosphoric acid (H3PO4): Ka1= 7.50x10-3; Ka2=6.20

shtirl [24]

Answer:

The pH of this solution is 1,350

Explanation:

The phosphoric acid (H₃PO₄) has three acid dissociation constants:

HPO₄²⁻ ⇄ PO4³⁻ + H⁺ Kₐ₃ = 4,20x10⁻¹⁰ (1)

H₂PO₄⁻ ⇄ HPO4²⁻ + H⁺ Kₐ₂ = 6,20x10⁻⁸ (2)

H₃PO₄ ⇄ H₂PO4⁻ + H⁺ Kₐ₁ = 7,50x10⁻³ (3)

The problem says that you have 10,00 mL of KH₂PO₄ (It means H₂PO₄⁻) 0,1000 M and you add 10,00 mL of HCl (Source of H⁺) 0,1000 M. So you can see that we have the reactives of the equation (3).

We need to know what is the concentration of H⁺ for calculate the pH.

The moles of H₂PO₄⁻ are:

10,00 mL × ( 1x10⁻⁴ mol / mL) = 1x10⁻³ mol

The moles of H⁺ are, in the same way:

10,00 mL × ( 1x10⁻⁴ mol / mL) = 1x10⁻³ mol

So:

H₃PO₄ ⇄ H₂PO4⁻ + H⁺ Kₐ₁ = 7,50x10⁻³ (3)

X mol ⇄ (1x10⁻³-X) mol + (1x10⁻³-X) mol (4)

The chemical equilibrium equation is:

Kₐ₁ = ([H₂PO4⁻] × [H⁺] / [H₃PO₄]

So:

7,50x10⁻³ = (1x10⁻³-X)² / X

Solving the equation you will obtain:

X² - 9,5x10⁻³ X + 1x10⁻⁶ = 0

Solving the quadratic formula you obtain two roots:

X = 9,393x10⁻³ ⇒ This one has no chemical logic because solving (4) you will obtain negative H₂PO4⁻ and H⁺ moles

X = 1,065x10⁻⁴

So the moles of H⁺ are : 1x10⁻³- 1,065x10⁻⁴ : 8,935x10⁻⁴ mol

The reaction volume are 20,00 mL (10,00 from both KH₂PO₄ and HCL)

Thus, the molarity of H⁺ ([H⁺]) is: 8,935x10⁻⁴ mol / 0,02000 L = 4,468x10⁻² M

pH is -log [H⁺]. So the obtained pH is 1,350

I hope it helps!

5 0

3 years ago

If you start with 0.30 m mn2 , at what ph will the free mn2 concentration be equal to 4.6 x 10-11 m?

aksik [14]

If you start with 0.30 m Mn₂ , at 12.5 pH, free Mn₂ concentration be equal to 4.6 x 10⁻¹¹ m

Initial molarity of Mn₂ = 0.30 M

Final molarity of Mn₂ = 4.6 x 10⁻¹¹

pH = ?

Ksp [Mn(OH)₂] = 4.6 x 10⁻¹⁴ (standard value)

Write the ionic equation

Mn(OH)₂ → Mn⁺² + 2OH⁻

[Mn⁺²] = 4.6 x 10⁻¹¹

We will calculate the concentration of OH⁻ by using Ksp expression

Ksp = [Mn⁺²][OH-]²

[Mn⁺²][OH⁻]² = 4.6 x 10⁻¹⁴

[OH⁻]² = 4.6 x 10⁻¹⁴ / 4.6 x 10⁻¹¹

[OH⁻]² = 10⁻³

[OH⁻] = (10⁻³)¹⁽²

[OH⁻] = 0.0316 M

Calculate the pOH

pOH = -log [OH⁻]

pOH = -log [0.0316]

pOH = 1.5

Now calculate pH

pH = 14 - pOH

pH = 14 - 1.5

pH = 12.5

You can also learn about molarity from the following question:

brainly.com/question/14782315

#SPJ4

7 0

1 year ago

A runner runs 4339 ft in 7.45 minutes. What is the runner's average speed in miles per hou 6.62 mi/hr O 0.110 mi/hr 6.618 mi/h e

slavikrds [6]

<u>Answer:</u> The average speed of the runner is 6.618 miles/hr

<u>Explanation:</u>

Average speed is defined as the ratio of total distance traveled to the total time taken.

To calculate the average speed of the runner, we use the equation:

$\text{Average speed}=\frac{\text{Total distance traveled}}{\text{Total time taken}}$

We are given:

Distance traveled = 4339 ft

Time taken = 7.45 mins

Putting values in above equation, we get:

$\text{Average speed of runner}=\frac{4330ft}{7.45min}=582.42ft/min$

To convert the speed into miles per hour, we use the conversion factors:

1 mile = 5280 ft

1 hr = 60 mins

Converting the speed into miles per hour, we get:

$\Rightarrow \frac{528.42ft}{min}\times (\frac{1miles}{5280ft})\times (\frac{60min}{1hr})\\\\\Rightarrow 6.618mil/hr$

Hence, the average speed of the runner is 6.618 miles/hr

6 0

3 years ago

Why is Earth's surface rarely impacted by large objects that enter Earth's 13 points

Hatshy [7]

Answer:

A.Because Earth's atmosphere causes most objects to burn up before they reach the surface.

Explanation:

The Earth's surface is rarely impacted by large objects that enters because the atmosphere causes most of the objects to burn up before they reach the surface.

There are different layers of the earth atmosphere which carries various amount of energy and energetic particles.

When a massive and a high solar object or dust or rocks are directed towards the earth, they are either deflected or burnt upon their passage through the atmosphere.
These energetic particles have ionizing properties and causes the solar particles to burn up.
This way the earth's surface is shielded from any impact of any sort.

6 0

3 years ago

What is the molarity of a 2.0L solution that was made up with 4.0 moles of NaCl?

Finger [1]

Answer:

[NaCl]: 2M

Explanation:

This solution is made of NaCl therefore:

Our solute is NaCl

Moles of solute: 4

Our solution's volume is 2L

Molarity are the moles of solute contained in 1L of solution (mol/L)

[NaCl]: 4 mol /2L = 2M

We can also make a rule of three:

In 2 L we have 4 moles of solute

So, In 1 L we must have (1 . 4) /2 = 2 M

8 0

3 years ago