) Calculate the pH of a polyprotic acid given and sketch the titration curves for the following reactions: (a) A 20.0-mL aliquot of 0.100M arsenic acid, H3AsO4, with 0.100M NaOH

Answers

Answer 1

Answer:

Following are the solution to the given question:

Explanation:

Let us indicate H3AsO4, an H3A triprotic acid; the ionising equations are as follows:

[tex]\to H_3A \Leftrightarrow H^+ + H_2A^- \\\\[/tex]

[tex]\to Ka_1 = \frac{[H^+][H_2A^-]}{[H_3A]}[/tex]

          [tex]= 10-2.2 = 6.31 \times 10^{-3} \ \ \ \ \ \ \ \ [since\ pKa_1 = 2.2\ and \ Ka = -\log_{10}(pKa)]\\[/tex]

[tex]\to H_2A^{-} \Leftrightarrow H^{+} + HA_2^{-}; \\[/tex]

[tex]\to Ka_2 = \frac{[H^+][HA_2^-]}{[H_2A^-]} = 10-6.8 = 1.58 \times 10^{-7} \\(since pKa2 = 6.8)\\\\\to HA_2^- \Leftrightarrow H^+ + A_3^- ;\\\\ \to Ka_3 = \frac{[H^+][A_3^-]}{[HA_2^-]} = 10-11.6 = 2.51 \times 10^{-12} \\ (given pKa_3 = 11.6)[/tex]

The initial pH; we've 0.00 mL of 0.100 M NaOH – H3A is the main species; Ka1>>Ka2>>Ka3 is also noted. They therefore ignore H2A's disconnection but set up next ICE chart.

[tex]\to H_3A \Leftrightarrow H^+ + H_2A^- \\\\[/tex]

[tex]initial \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ 0.100 \ \ \ \ \ \ \ \ \ \ \ \ \ \ 0 \ \ \ \ \ \ \ \ \ \ \ \ \ \ 0 \\\\[/tex]

[tex]change \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ - x \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ + x \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ + x\\\\equilibrium \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ (0.100 - x) \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ x \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ x\\\\[/tex]

[tex]Ka_1 = \frac{[H^+][H_2A^-]}{[H_3A]} = \frac{(x)(x)}{(0.100 - x)}[/tex]

[tex]\text{x to be much smaller than 0.100 M}\\\\to 6.31 \times 10^{-3} = \frac{x^2}{0.100}\\\\\to x^2 = 6.31 \times 10^{-4}\\\\ \to x = 0.025\ M\\\\\to pH = -\log_{10}[H^+] = -\log_{10}(0.025) = 1.60[/tex]


Related Questions

Which statement best explains why cells separate and expel waste?

Answers

Answer:

I would say the 2nd one It helps growth and repair of cells of orgasmsBut your school would probably say the 3rd one It helps remove toxins from the body to maintain homeostasis

Explanation:

2. Our cells produce a lot of waste that must be eliminated (excreted) from the body. These residues are called excreta. The residues formed from the chemical reactions that take place inside the cells can be eliminated through:

• of the respiratory system (carbon dioxide)

• skin (sweat)

urinary system (urine)

Our cells expel these substances to maintain the dynamic balance (homeostasis) of our body and promote our well-being.

1- What is the mass of 5.5 mole of sodium?
2- How many moles in 230 grams of water?
3- What is the mass of 4.5 mole of lithium chloride?
4- How many moles in 750 grams of sodium chloride?

Answers

Answer:

1. 126.44 or 126.4

2. 12.766 or 12.8

3.190.77 or 190.8

4.12.833 or 12.8

Explanation:

One way to account for the mass "lost" in a reaction that involves a gas would be to________.

Answers

Answer:

Place the experiments on a scale

Explanation:

If you place two of the same experiments on a scale, and cover one with a cup, the one with the cup will "lose" mass, while the other won't, due to the cup being a "containment field" I guess you could call it.

how much potassium bromide will form a saturated solution with 100 grams of water at 40 degrees celsius

Answers

Answer:

75.4 g.

Explanation:

Hello there!

In this case, since the solubility stands for the maximum amount of a solute that is completely dissolved in a specific amount of solvent, typically 100 g of water as the universal solvent; we need to take into account that the higher the temperature the higher the solubility for the most of the solids.

In such a way, since the solubility of potassium bromide at 20 °C is 65.3 g per 100 g of water, at 40 °C is 75.4 g per 100 g of water, proving the aforesaid. Therefore, 75.4 g of potassium bromide will form a saturated solution with 100 g of water at 40 °C.

Regards!

Chemistry
Definition in your own words
Will check if you got it from online.


Word: Phase change

Answers

Answer:

See explanation.

Explanation:

Hello!

In this case, considering the concept of phase change, we understand that it is related how the phases of matter, solid, liquid and gas, are related to each other for a specific substance.

For instance, when going over water, we notice that its most common phase at this atmospheric conditions is the liquid phase; however, if it starts losing energy (being cooled down) its molecules tend to get together and freeze, undergoing a phase change to solid. On the other hand, if heated up, its molecules will be able to get farther to each other and therefore undergo a phase change to gas.

Thus, we can realize that a phase change is also explained molecularly; because when a substance undergo a phase change, its molecules rearrange, according to the addition or removal of energy and therefore get to another phase.

Best regards!


What is the balanced, net ionic equation for the reaction shown below?
Pb(NO3)2(aq) + H2SO4(aq) + PbSO4(s) + 2 HNO3(aq)

Answers

The net ionic equation :

Pb²⁺(aq)+SO₄²⁻(aq) ⇒ PbSO₄(s)

Further explanation

Given

Reaction

Pb(NO3)2(aq) + H2SO4(aq) + PbSO4(s) + 2 HNO3(aq)

Required

The net ionic equation

Solution

The equation of a chemical reaction can be expressed in the equation of the ions

In the ion equation, there is a spectator ion that is the ion that does not change (does not react) because it is present before and after the reaction

When these ions are removed, the ionic equation is called the net ionic equation

For gases and solids including water (H₂O) can be written as an ionized molecule

Ionic equation :

Pb²⁺(aq)+ 2NO₃⁻(aq) + 2H⁺(aq)+SO₄²⁻(aq) ⇒ PbSO₄(s) + 2H⁺(aq)+NO₃⁻(aq)

2NO₃⁻(aq) + 2H⁺(aq) ⇒ a spectator ions

The net ionic equation :

Pb²⁺(aq)+SO₄²⁻(aq) ⇒ PbSO₄(s)

The net ionic equation is   Pb²⁺(aq)+SO₄²⁻(aq) ⇒ PbSO₄(s)

The given equation is

Pb(NO3)2(aq) + H2SO4(aq) + PbSO4(s) + 2 HNO3(aq)

Writing its ionic equation

Pb²⁺(aq)+ 2NO₃⁻(aq) + 2H⁺(aq)+SO₄²⁻(aq) ⇒ PbSO₄(s) + 2H⁺(aq)+NO₃⁻(aq)

Now the ionic equation contains spectator ions that do not react. They are present in both the reactant and the product.  When these ions are removed, the ionic equation is called the net ionic equation.

2NO₃⁻(aq) + 2H⁺(aq) ⇒ a spectator ions

The net ionic equation is:

Pb²⁺(aq)+SO₄²⁻(aq) ⇒ PbSO₄(s)

Learn more:

https://brainly.com/question/19046605

Can y’all help me with this question How many atoms are found in the chemical formula below Al2( SiO3)2

Answers

Answer:

the answer is 10

Explanation:

Al2 is 2 atoms by itself

(SiO3)2 is 8 because Si is a single atom and O3 is 3 oxygen atoms but because of the subscript outside of the parentheses it doubles and becomes 2 and 6 respectively

I NEED HELP REALLY BAD AND THIS IS DUE IN 5 MINSSS

The successive ionization energies for a given element are listed. How many valence electrons does it have?

Answers

Answer:

5

Explanation:

The number of valence electrons in the atom is 5 as can be seen from the ionization energy.

Ionization energy is the measure of the readiness of an atom to lose an electron. The lower the value the easier it is for an atom to lose an electron and vice versa.

After the removal of the first electron it becomes increasingly more difficult to remove succeeding electrons because of the imbalance between the positive nuclear charge and the remaining electrons.

Therefore, since we have 5 ionization energies given, the number of valence electrons in this atom is 5.

! 20 points !need answer FAST!
In nuclear reactions, how can huge amounts of energy be produced?
A. By converting chemical energy into nuclear energy
B. By releasing thermal energy in uranium
C. By creating energy from the surrounding space
D. By destroying matter to create energy

Answers

Answer:

C.

Explanation: In nuclear fission and fusion reactions, some of the energy in matter is converted to energy.  If you weigh the reactants and the products, the products will weigh less than the reactants.  This is called the mass defect and is the result of turning matter into energy.

Answer:

D.

Explanation:

With the Fat Boy and Little Boy nuclear bombs that were drop on Japan, They used a little gun (inside the bomb) that shot a little slug. this hit and caused a chain reaction that caused the bomb to detonate. This released much energy. Destroying much of the two cities when the bombs were dropped.

list 3 things that make the index contour unique

Answers

Answer:

htoybuuo

t857 NJ n8

u. t i ukuo. jl

What is the “Island of Stability”?

Answers

Answer:

The island of stability is a term from nuclear physics that describes the possibility of elements with particularly stable "magic numbers" of protons and neutrons. This would allow certain isotopes of some transuranic elements to be far more stable than others, that is, decay much more slowly.

Explanation:

A. Energy is transferred to different forms
B. Energy can be destroyed in different forms
C. Energy is created
D. Energy is released during a combustion

Answers

Answer:

A. Energy is transferred to different forms .

Explanation:

Hello!

In this case, we need to consider the law of conservation of mass and energy which states that mass and energy cannot be neither created nor destroyed, just modified; it means we can rule out B. and C. so far.

Moreover, since D. is actually true for combustion reactions because they are used to provide energy in industrial operations, this is not the concern here because a combustion reaction is not considered.

Therefore the correct option is A. Energy is transferred to different forms as the energy provided by Rose is transferred to the pendulum system .

Best regards!

Which is the lowest energy level having “d” orbitals?

Answers

Answer:

n=3 the minimum n for which d orbital exist.

Which of the following is a chemical weathering agent?

1.) acid produced by plants growing on rocks

2.) growing tree roots

3.) burrowing animals

4.) ice wedging

PLEASE HELP ME FAST ASAP

Answers

Answer:

1. acid produced by plants growing on rocks

plz give me BRAINLIEST answer

0.72-mol sample of is put into a 1.00-L vessel and heated. At equilibrium, the vessel contains 0.40 mol of and 0.40 mol of . Calculate the value of the equilibrium constant for the decomposition of to and at this temperature.

Answers

Answer:

0.50

Explanation:

A 0.72-mol sample of PCl₅ is put into a 1.00-L vessel and heated. At equilibrium, the vessel contains 0.40 mol of PCl₃(g) and 0.40 mol of Cl₂(g). Calculate the value of the equilibrium constant for the decomposition of PCl₅ to PCl₃ and Cl₂ at this temperature.

Step 1: Calculate the molar concentrations

[PCl₅]i = 0.72 mol/1.00 L = 0.72 M

[PCl₃]eq = 0.40 mol/1.00 L = 0.40 M

[Cl₂]eq = 0.40 mol/1.00 L = 0.40 M

Step 2: Make an ICE chart

        PCl₅(g) ⇄ PCl₃(g) + Cl₂(g)

I        0.72           0            0

C         -x            +x          +x

E      0.72-x          x           x

Step 3: Determine the value of x

Since [PCl₃]eq = [Cl₂]eq = 0.40 M, x = 0.40 M

Step 4: Determine the concentration of PCl₅ at equilibrium

[PCl₅]eq = 0.72-x = 0.72-0.40 = 0.32 M

Step 5: Calculate the equilibrium constant

Kc = [PCl₃] × [Cl₂] / [PCl₅]

Kc = 0.40 × 0.40 / 0.32 = 0.50

what is chemical reaction?

Answers

Answer:

a process that involves rearrangement of the molecular or ionic structure of a substance, as distinct from a change in physical form or a nuclear reaction

A chemical reaction is a process where one or more substances or reactants are converted to one or more different substances or products. a chemical reaction rearranges the constituent atoms of the reactants to create different products

What's the charge on Ni in the compound NiCi3? *
+1
+2.
+3
- 7
-2.
3
you can't tell

Answers

Answer:

+3

Explanation:

Chlorine is anion with a -1 charge. But they are three chlorine atoms.

-1 * 3 = -3

So they have a -3 charge.

So to balance the compound, the nickel has to be a cation with a +3 charge.

-3 + 3 = 0

Furthermore, a chemical bond always has a 0 charge. Remember that.

Hope it helped! Rate my answer a 5 star if correct.

Aluminum has density of 2.7g/cm3.

What is the mass of 35 cm3 aluminum in g?

Answers

Answer:

density= 2.7 g/cm3

volume= 25 cm3

mass = density× volume

= 35×2.7

= 94.5 g

Which of the following statements about sidestream smoke is not true?

a. It is the smoke that a smoker inhales from a cigarette.

b. It is dirtier and has a different chemical makeup than mainstream smoke.

c. It is the smoke that people around the smoker inhale.

d. It is the smoke that results from the burning end of a cigarette.

Answers

Answer: a

Explanation: the smoker actually exhales the sidestream smoke

how much °f of 35°C ?
help me please

Answers

Answer: 95 degrees fahrenheit hope this helps :]

Explanation:

Density of gold is 19.3g/cm^3 what is the density in lbs/in^3 units

Answers

The density in lbs/in³ units : 0.697

Further explanation

Given

Density of gold is 19.3 g/cm³

Required

Conversion to  lbs/in³

Solution

Density is a quantity derived from the mass and volume  

Density is the ratio of mass per unit volume  

Density formula:  

[tex]\large {\boxed {\bold {\rho ~ = ~ \frac {m} {V}}}}[/tex]

Conversion factor

1 g =  0,00220462 lbs

1 cm³ = 0,0610237 in³

So the density :

[tex]\tt 19.3~\dfrac{g}{1~cm^3}\times \dfrac{cm^3}{0.0610237~in^3}\times \dfrac{0.00220462~lbs}{1~g}=0.697~lbs/in^3[/tex]

Mass of 2×10^21 number of atoms of an element is 0.4g. What is the mass of 0.5 mole of the element?

Answers

Answer:

66.7 g

Explanation:

Number of atoms = 2×10²¹

Mass of 2×10²¹ atoms = 0.4 g

Mass of 0.5 moles of that element = ?

Solution:

1 mole contain 6.022×10²³ atoms

2×10²¹ atoms × 1 mol / 6.022×10²³ atoms

0.33×10⁻² mol

0.003 mol

 0.003 mole have mass of 0.4 g

0.5 mol have mass 0.5/0.003×0.4 g = 66.7 g

what is the pressure of the dry gas alone ?

Answers

P O₂ = 736.2 torr

Further explanation

Given

P tot=760 torr

P H₂O = 23.8 torr

Required

P gas/O₂

Solution

Dalton's law of partial pressures stated that

the total pressure of a mixture of gases is equal to the sum of the partial pressures of the component gases  

Can be formulated:  

P tot = P1 + P2 + P3 ....  Pn

P tot = P H₂O + P O₂

760 torr = 23.8 torr + P O₂

P O₂ = 760 - 23.8

P O₂ = 736.2 torr

write a skeletal equation for the following reaction: An aqueous solution of barium nitrate and an aqueous solution of sodium sulfate are mixed together. Then balance the completed chemical equation.

Answers

Answer: skeletal equation : [tex]Ba(NO_3)_2(aq)+Na_2SO_4(aq)\rightarrow NaNO_3(aq)+BaSO_4(s)[/tex]

The products are sodium nitrate and barium sulphate.

balanced equation :  [tex]Ba(NO_3)_2(aq)+Na_2SO_4(aq)\rightarrow 2NaNO_3(aq)+BaSO_4(s)[/tex]

Explanation:

A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.  

The skeletal equation is:

[tex]Ba(NO_3)_2(aq)+Na_2SO_4(aq)\rightarrow NaNO_3(aq)+BaSO_4(s)[/tex]

The balanced chemical equation is:

[tex]Ba(NO_3)_2(aq)+Na_2SO_4(aq)\rightarrow 2NaNO_3(aq)+BaSO_4(s)[/tex]

What is matter? Choose the best answer.

A Anything that is solid

B Anything that takes up space

C Anything that has a fixed volume

D Anything that can be seen

Answers

Answer:

B

Explanation:

The answer is B because matter is everything

Identify the missing particle in the following nuclear equation.
aPlatinum-199
bMercury-198
cMercury-199
dPlatinum-198

Answers

Answer:

c

Explanation:

I need help with science. picture attached

Answers

Answer:

there is no picture.

Explanation:

There is no picture child anyway soo...

What is radiative equilibrium?

Answers

Answer:

Radiative equilibrium is the condition where the total thermal radiation leaving an object is equal to the total thermal radiation entering it. It is one of the several requirements for thermodynamic equilibrium, but it can occur in the absence of thermodynamic equilibrium.

Answer:

Radiative equilibrium is the condition where the total thermal radiation leaving an object is equal to the total thermal radiation entering it. It is one of the several requirements for thermodynamic equilibrium, but it can occur in the absence of thermodynamic equilibrium.

Hope this helps :)

When solutions of acetic acid and sodium hydroxide react, which of the following are not present in the net ionic equation?
I. hydrogen ion
II. acetate ion
III. sodium ion
IV. hydroxide ion
A) I and II.
B) I, II, and III.
C) I and IV.
D) I and III.
E) II and III.

Answers

Answer:

E) II and III.

Explanation:

Let's consider the complete ionic equation when solutions of acetic acid and sodium hydroxide react. It includes all the ions and molecular species.

CH₃COO⁻(aq) + H⁺(aq) + Na⁺(aq) + OH⁻(aq) ⇒ CH₃COO⁻(aq) + Na⁺(aq) + H₂O(l)

The net ionic equation includes only the ions that participate in the reaction and the molecular species.

H⁺(aq) + OH⁻(aq) ⇒ H₂O(l)

The species not present are:

II. acetate ion

III. sodium ion

Which of these reservoirs contains the most water?

Answers

Answer:

Glaciers

Explanation:

Reservoirs refers to paces where water are stored. The largest water reservoir on earth are the oceans which contain about 97% of all the water on the earth.

The next highest  reservoir  are the glaciers or the polar ice caps. These hold quite an enormous amount of the water found on earth.

Surface and other fresh water only account for about 1.2% of all the surface water on earth.Ground water accounts for a very minute percentage of the water found on earth.

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