A mixture is prepared using 27.00 mL of a 0.0758 M weak base (pKa=4.594) , 27.00 mL of a 0.0553 M weak acid (pKa=3.235) and 1.00 mL of 1.25×10−4 M HIn and then diluting to 100.0 mL, where HIn is the protonated indicator. The absorbance measured at 550 nm in a 5.000 cm cell was 0.1102 . The molar absorptivity (????) values for HIn and its deprotonated form In− at 550 nm are 2.26×104 M−1cm−1 and 1.53×104 M−1cm−1 , respectively. What is the pH of the solution?

Answers

Answer 1

Answer:

pH = 4.164

Explanation:

The first process is to find the initial moles for the base (B) & the acid (HA)

i.e.

[tex]= \dfrac{27 mL \times 0.0758 \ moles \ \ of \ B}{1000 \ mL}[/tex]

[tex]=0.0020466[/tex]

[tex]\simeq 2.047\times 10^{-3} \ moles \ of \ B[/tex]

[tex]= \dfrac{27 mL \times 0.0553 \ moles \ \ of \ HA}{1000 \ mL}[/tex]

[tex]=0.0014931[/tex]

[tex]\simeq 1.493\times 10^{-3} \ moles \ of \ HA[/tex]

The acid with base reaction is expressed as;

          HA              +      B         →             A⁻            +         HB⁺

to    1.493 × 10⁻³       2.047 × 10⁻³             -                         -

    -  1.493 × 10⁻³       1.493 × 10⁻³         1.493 × 10⁻³         1.493 × 10⁻³

            0                    5.54 × 10⁻⁴         1.493 × 10⁻³         1.493 × 10⁻³

From observation; both the acid & base weak

Given that:

The pKa for base = 4.594

The pKa for acid = 3.235

Recall that;

pKa = -log Ka

So; Ka = [tex]\mathbf{10^{-Ka}}[/tex]

By applying this:

For Base; Ka = [tex]10^{-4.594}[/tex] = 2.5468 × 10⁻⁵

For Acid:  Ka = [tex]10^{ -3.235}[/tex] = 5.821 × 10⁻⁴

After the reaction; we have the base with its conjugate acid & conjugate base of acid; Thus, since the conjugate acid of the base possesses a higher value of K, it is likely it would be the one to define the pH of the solution.

By analyzing the system, we have:

              HB⁺         + H₂O           ↔           B          +            H₃O⁺

     [tex]\dfrac{1.493\times 10^{-3}}{0.1 \ L}[/tex]                                 [tex]\dfrac{5.54\times 10^{-4}}{0.1 \ L}[/tex]

to   0.01493 M                                 0.00554   M

  -      x                                                   x                                x

    0.01493 - x                                 0.00554 - x                     x

Thus;

[tex]2.5468 \times 10^{-5} = \dfrac{(0.00554 -x)\times x}{(0.01493-x)}[/tex]

Using the common ion effect;

0.00554 - x   [tex]\simeq[/tex]  0.00554   &

0.01493 -  x   [tex]\simeq[/tex]   0.01493

[tex]x = \dfrac{2.5468 \times 10^{-5} \times 0.01493}{0.00554}[/tex]

x =  [H₃O⁺] = 6.8635  × 10⁻⁵

pH = -log(6.8635  × 10⁻⁵)

pH = 4.164


Related Questions

True or False: All metals have high melting points.

Answers

Answer:

True. All metals have a melting point when it reaches a certain degree of temperature

Explanation:

Name the following hydrocarbon:
CH3CH2CH2CH2F
A. 4-fluorobutane
B. 2-fluorobutane
C. 1-fluorobutane
D. 1-fluoropentane

Answers

Answer:

The correct answer is (C)

Which is "1-fluorobutane"

Explanation:

Hope this helped if so please leave a "Rating" and "Like" and MARK me Brainliest if it was the BEST answer! THANKS! :)

The name of the hydrocarbon CH3CH2CH2CH2F is 1-fluorobutane.

In naming organic hydrocarbons, we count the number of the parent chain family. Here, we have an alkane with 4 carbons, which means that the parent chain is a family of alkane. The fourth compound in the family of an alkane is butane.

Afterwards, we will determine if there is any substituent attached to any of the carbon atoms in the chain and rank them in a way such that we have the lowest possible number.

Here, the fluorine is attached to the first carbon atom. So, it becomes 1-fluorobutane.

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What will happen to the following equilibrium if Cl2
was removed ?
4HCI(9) + O2(9) = 2012(9) + 2H20(9)

Answers

The following equilibrium will shift in the direction of the product:

Further explanation

Given

Reaction

4HCl + O₂ → 2H₂O + 2Cl₂

Cl₂  was removed

Required

Equilibrium changes

Solution

Reaction = - action

adding the products ⇒ Shifts in the direction of the reactants

reducing the products ⇒Shifts in the direction of the products

Cl₂ as a product, so if Cl₂ is taken or reduced, the reaction will try to maintain system equilibrium by moving to the right (product formation) ⇒ Shift in the direction of the product:

An angle of refraction is the angle between the refracted ray and the

incident ray.
normal.
medium.
boundary.

Answers

Answer:

Normal

Explanation:

with the boundary, is a glancing angle

with the incident ray, is the field of view

Answer:

B. normal

Explanation:

What is GRAVITY and WHO discovered it? *

Answers

Answer:

Newton discovered it.

Explanation:

Gravity is the attraction between the earth and any object. and gravitational force is the attraction between any two objects.

Answer:

gravity is a force that pulls things towards each other

Explanation:

issac newton is the one who discovered it

for each pair of compounds below , identify the one that would be expected to have more ionic character.explain you choice. (a)NaBr or HBr (b)BrCl or FCl​

Answers

Answer:

a)NaBr

b)FCl

Explanation:

To identify which compound is more ionic we will calculate the electronegativity difference.

A) NaBr

Electronegativity of Na = 0.93

Electronegativity of Br = 2.96

Electronegativity difference = 2.96- 0.93 = 2.03

HBr

Electronegativity of H = 2.2

Electronegativity of Br = 2.96

Electronegativity difference = 2.96 - 2.2 = 0.76

NaBr have more ionic character because of large electronegativity difference.

B) BrCl

Electronegativity of Cl = 3.16

Electronegativity of Br = 2.96

Electronegativity difference = 3.16 - 2.96 = 0.2

FCl

Electronegativity of F = 3.98

Electronegativity of Br = 2.96

Electronegativity difference = 3.98 - 2.96 = 1.02

FCl have more ionic character because of large electronegativity difference.

At which point is crust neither created nor destroyed?

island chain
mid-ocean ridge
divergent boundary
transform boundary

Answers

Answer:

transform battery

Explanation:

Answer: D. Transform Boundary

Explanation: I did the test.

Why is light a wave?​

Answers

Answer:

an electromagnetic wave

Explanation:

why is it important to prepare for disaster? what are the things you need to prepare?​

Answers

Explanation:

The reason why it is important to prepare for an disaster is because Being prepared can reduce fear, anxiety, and losses that accompany disasters. People also can reduce the impact of disasters (flood proofing, elevating a home or moving a home out of one's harm's way, and securing items that could shake loose in an earthquake) and sometimes avoid the danger completely.

The things you need to prepare for an disaster is

WaterFoodClothing Money if neededFlash lightBatteriesFirst aid kitYou can even need an radio( to keep updated).

In science why is it important to explain why the evidence supports your claim?

Answers

In science it’s important to explain the evidence that supports your claim because in science it’s more about what you willing to do

Show the calculation of the molality of a solution made by dissolving 15.9 grams of Ca3(PO4)2 in 400 grams of water.

Answers

The molality of a solution : 0.128 m

Further explanation

Given

15.9 g of Ca3(PO4)2 in 400 grams of water.

Required

The molality

Solution

molality = mol solute / kg solvent

solute= Ca3(PO4)2(MW=Molecular Weight: 310.2 g/mol)

mol solute :

[tex]\tt \dfrac{15.9}{310.2}=0.0512[/tex]

The molality :

[tex]\tt \dfrac{0.0512}{0.4~kg}=0.128~m[/tex]

1) Compounds Y and Z both have the formula C9H18.
Both Y and Z react with one molar equivalent of hydrogen in the presence of a palladium catalyst to form 2-methyloctane.
The heat of hydrogenation of Y is less than that of Z.
Y and Z each undergo hydroboration/oxidation to give a primary alcohol (OH attached to a primary carbon).
What is the structure of Y?
2) Compound X has the formula C8H12.
X reacts with two molar equivalents of hydrogen in the presence of a palladium catalyst to form cyclooctane.
Treatment of X with ozone followed by zinc in aqueous acid gives two molar equivalents of the same dialdehyde.
What is the structure of X

Answers

Answer:

See explanation and images attached

Explanation:

We know that the cis isomer has more heat of hydrogenation since it is less stable than the trans isomer. Since the hydrogenation of both compounds yields the same product and the hydroboration/oxidation both give a primary alcohol, they are geometric isomers and Y is the trans isomer (Image 2).

For the compound C8H12, the compound in question must be 1,5- cyclooctadiene since two moles of the same aldehyde was obtained after ozonolysis and reaction with two equivalents of hydrogen gives cyclooctane (Image 1).

(plsss help meh.) Describe how you could find the density of a gold crown.

Answers

Answer:

Below! ;)

Explanation:

The formula for finding density is:

Mass/Volume

So for example I have a cube, it has a mass of about 20 grams (not weight) and it's dimensions are about an inchxinchxinch. So basically it is a 20 gram cubic inch cube.

So to find it's density I have to divide mass(=20)/Volume(=1 inch^3). or simplified, 20 ÷ 1 = 20

So the density of my cube is 20..

Hope this helps!

Have a nice day!

If you find my answer helpful

Pls consider marking my answer as Brainliest! It would mean a lot!

Type the correct answer in the box. Express your answer to three significant figures.

A balloon is filled with 0.250 mole of air at 35°C. If the volume of the balloon is 6.23 liters, what is the absolute pressure of the air in the balloon?

Answers

Answer:

102.807 kPa

Explanation:

There are some assumptions to be made in the answer. The air inside the balloon acts as an ideal gas at a given temperature conditions.

Using the combined ideal gas equation.

P= absolute pressure of the air inside the balloon.

V= volume of air inside the balloon (6.23 L= 6.23 * 10⁻³ m³)

n= moles of gas(air). (0.250 mol)

R= Universal gas constant ( 8.314 J / mol·K)

T= Temperature in Kelvin

T= 35 + 273.15 = 308.15 K

P= 102.807 * 10³ Pa

P= 102.807 kPa

Which term best describes the molecule shown below?

Answers

Answer:

Unsaturated alkene

Explanation:

other answer was wrong

There are two types of chemical compound one is covalent compound and other is ionic compound, covalent compound formed by sharing of electron and ionic compound formed by complete transfer of electron. Therefore, the correct option is option D.

What is chemical Compound?

Chemical Compound is a combination of molecule, Molecule forms by combination of element and element forms by combination of atoms in fixed proportion.

An ionic compound is a metal and nonmetal combined compound.  Ionic compound are very hard. They have high melting and boiling point because of strong ion bond.

There are two types of compound in organic chemistry, one is saturated and other is unsaturated. Saturated is the one which possess all single bond and unsaturated is the one which possess either double or triple bond. The given chemical compound is unsaturated alkene.

Therefore, the correct option is option D.

To learn more about chemical compound, here:

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How many hydrogen molecules are needed to produce two H2O molecules

Answers

Answer:

There are 2 Hydrogen molecules in H2O

Explanation:

if you look at the symbol for Hydrogen (H) you see that there is a number beside it, to the right. That number shows how many molecules there are of that element.

(Sidenote: If there is no number there is only one molecule)

Hope this helped :)

There are 2per molecules But the question is asking for 2 molecules of it so 2x2= 4... 4 is the answer!

the initial internal energy of a system is 43.5kj. it absorbs 8.3kj of heat while performing 3.5kj of work on the surroundings. what is its final internal energy?
Shows works to help me understand what I did wrong.

Answers

Answer:

[tex]U_2=48.3kJ[/tex]

Explanation:

Hello!

In this case, since the fist law of thermodynamics helps us to understand how the change in internal energy is defined in terms of the head added to the system and the work done by the system:

[tex]Q+W=\Delta U[/tex]

In such a way, since 8.3 kJ of heat are absorbed by the system, 3.5 kJ are done by the system and the initial internal energy is 43.5 kJ, the final internal energy turns out:

[tex]U_2=U_1+Q-W\\\\U_2=43.5kJ+8.3kJ+3.5kJ\\\\U_2=48.3kJ[/tex]

Best regards!

3Ba2+(aq) + 2PO43−(aq) ⇌ Ba3⎛⎝PO4⎞⎠2(s). Is Kc> 1, < 1, or ≈ 1?

Answers

Answer:

Kc < 1

Explanation:

Since the product formed is in solid state, from law of mass action.

Kc = 0

[Ba2+]³[PO4³-]²

hence Kc is 0

A mirror forms an image because of which behavior of light?

refraction
reflection
diffraction
absorption

Answers

Answer: reflection

Explanation:

A mirror forms an image because of reflection of light. Therefore, the correct option is option B among all the given options.

What is light?

Light is the electromagnetic radiation that is visible with the eye. Electromagnetic radiation has a very broad wavelength range, ranging from gamma rays having wavelengths shorter than around 1 1011 metre to radio waves with wavelengths measured in metres.

The spectral areas next to the visible band, infrared at one end as well as ultraviolet at the other, are often commonly referred to as light. The velocity of light in the vacuum is indeed a basic physical constant, with the current accepted value being 299,792,458 meters per second, or approximately 186,282 miles a second. A mirror forms an image because of reflection of light.

Therefore, the correct option is option B.

To learn more about light, here:

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You want to measure the volume of a gold bracelet. For this purpose, a specimen with 20 mL of water is available; when inserting the bracelet, the water level rises to 25 mL. If the density of gold is 19300 Kg/m3. What will be the mass of the bracelet?

Answers

Answer:

volume of bracelet is 5cm3

mass is 0.0965Kg

Explanation:

1ml = 1cm3

1m3 = 1000000cm3

0.000005m3

Mass = volume*density

19300 Kg/m3 * 0.000005m3 = 0.0965Kg

How many moles of copper are in 6,000,000 atoms of copper?

Answers

Answer: There will be 9.9632 × 10⁻¹⁸ moles of Copper in 6,000,000 atoms of Copper.

What statement is not true about the field of science

Answers

Answer:

where are the statements?

Explanation:

butane
methane
ethane
propane

Answers

Further explanation

Given

the structure of the alkanes

Required

match the image to the name

Solution

Alkanes are saturated hydrocarbons with all of the carbon bonds being single bonds

General formula:

[tex]\large {\boxed {\bold {C_nH_2n + 2}}}[/tex]

If we look at the picture, we define the black atom as Carbon and the branch is Hydrogen

To determine the name of the alkane, all we have to do is count the number of Carbon atoms

Butane : C₄H₁₀ : 4 C atoms

Methane : CH₄ : 1 C atom

Ethane : C₂H₆ : 2 C atoms

Propane : C₃H₈ : 3 C atoms


Explain how atomic
radius, valence electrons
and effect nuclear charge
creates the trend for metal
reactivity.

Answers

Answer:A higher effective nuclear charge causes greater attractions to the electrons, pulling the electron cloud closer to the nucleus which results in a smaller atomic radius. Down a group, the number of energy levels (n) increases, so there is a greater distance between the nucleus and the outermost orbital.

Answer:

A higher effective nuclear charge causes greater attractions to the electrons, pulling the electron cloud closer to the nucleus which results in a smaller atomic radius. Down a group, the number of energy levels increases, so there is a greater distance between the nucleus and the outermost orbital.Explanation:

when coal goes through combustion it releases nitrogen and sulpur into the air in the form of what

Answers

Answer:

Over time, the plant matter transforms from moist, low-carbon peat, to coal, All types of coal also contain sulfur, which, when burned, releases toxic air pollution. Sulfur All this coal comes from mines, which are either underground or run on diesel—a major source of air toxins, nitrogen oxide, and soot.

what does the phrase sea of electrons describe?? please help

Answers

Answer: Metallic Bonding.In metallic bonds, the valence electrons from the s and p orbitals of the interacting metal atoms delocalize. That is to say, instead of orbiting their respective metal atoms, they form a “sea” of electrons that surrounds the positively charged atomic nuclei of the interacting metal ions.

Explanation:

What is rate of reaction?​

Answers

Answer:

The reaction rate or rate of reaction is the speed at which a chemical reaction takes place. Reaction rate is defined as the speed at which reactants are converted into products. Reaction rates can vary dramatically.

Explanation:

PLS MAKE ME AS BRAINLIST

Reaction rate, in chemistry, the speed at which a chemical reaction proceeds. It is often expressed in terms of either the concentration (amount per unit volume) of a product that is formed in a unit of time or the concentration of a reactant that is consumed in a unit of time.

What ratio of concentration of ammonia and ammonium chloride should be mixed to
prepare a buffer solution of pOH 5? (Kb for NH3 =1.8 x 10-4)​

Answers

The ratio of concentration of ammonia and ammonium chloride : 0.05

Further explanation

Given

pOH=5

Kb for NH3 =1.8 x 10-4

Required

The ratio of concentration of ammonia (NH₃) and ammonium chloride(NH₄Cl)

Solution

Solutions containing ammonia and its salt: ammonium chloride are called alkaline buffers

Can be formulated : ( for the same of the volume, mol=concentration)

[tex]\tt \displaystyle [OH-]=Kb\times\frac{weak\:base\:mole}{salt\:mole\times valence}[/tex]

pOH=-log [OH⁻]

pOH=5⇒[OH⁻]=10⁻⁵

Valence for NH₄Cl = 1, so the concentration ratio :

[tex]\tt 10^{-5}=1.8\times 10^{-4}\times \dfrac{[~NH_3]}{[NH_4Cl]}\\\\0.05=\dfrac{[~NH_3]}{[NH_4Cl]}[/tex]

The pressure of a sample of argon gas was increased from 3.89 atm to 8.73 atm at constant temperature. If the final volume of the argon sample was 18.4 L, what was the initial volume of the argon sample? Assume ideal behavior.

Answers

Answer:

41.29 L

Explanation:

The initial volume can be found by using the formula for Boyle's law which is

[tex]P_1V_1 = P_2V_2[/tex]

Since we are finding the initial volume

[tex]V_1 = \frac{P_2V_2}{P_1} \\[/tex]

From the question we have

[tex]V_1 = \frac{8.73 \times 18.4}{3.89} = \frac{160.632}{3.89} \\ = 41.293573...[/tex]

We have the final answer as

41.29 L

Hope this helps you

A limited number of the many known elements comprise the largest portion of living matter. Group Elements A Calcium, Phosphorus, Oxygen, Sulfur B Cobalt, Hydrogen, Oxygen, Nitrogen C с Helium, Oxygen, Sulfur, Carbon Hydrogen, Oxygen, Nitrogen, Carbon 1 1 Which group of elements above comprises the largest portion of living matter? A Group A B Group B C Group C D Group D​

Answers

Answer:

Explanation:

Hydrogen oxygen nitrogen and carbon

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