A 25.0 mL solution of quinine was titrated with 0.50 M hydrochloric acid, HCl. It was found that the solution contained 0.100 moles of quinine. What was the pH of the solution after 50.00 mL of the HCl solution were added

Answers

Answer 1

Answer:

[tex]pH=11.45[/tex]

Explanation:

Hello there!

In this case, since the chemical equation representing the neutralization of the weak base quinine can be written as follows:

[tex]C_{20}H_{24}N_2O_2+HCl\rightarrow C_{20}H_{25}N_2O_2^+Cl^-[/tex]

Whereas we have 0.100 moles of the base and those of acid as shown below

[tex]n_{acid}=0.50molHCl/L*0.05000L=0.025molHCl[/tex]

Which means that the remaining moles of quinine are:

[tex]n_{C_{20}H_{24}N_2O_2}^{final}=0.100mol-0.025mol=0.075mol[/tex]

And the resulting concentration:

[tex][C_{20}H_{24}N_2O_2]=\frac{0.075mol}{(0.025+0.050)L} =1.00M[/tex]

Now, the calculation of the pH requires the pKb of quinine (5.1) as its ionization in water produces OH- ions:

[tex]C_{20}H_{24}N_2O_2+H_2O\rightleftharpoons OH^-++C_{20}H_{25}N_2O_2^+[/tex]

And the equilibrium expression is:

[tex]Kb=\frac{[C_{20}H_{24}N_2O_2][C_{20}H_{25}N_2O_2 ^+]}{[C_{20}H_{24}N_2O_2]} \\\\10^{-5.1}=\frac{x^2}{1.00M}\\\\ 7.94x10^{-6}=\frac{x^2}{1.00M}[/tex]

Which is solved for x as follows:

[tex]x= \sqrt{7.94x10^{-6}*1.00M}\\\\x=0.00282M[/tex]

Which means the pOH is:

[tex]pOH=-log(0.00282)=2.55[/tex]

And the pH:

[tex]pH=14-2.55\\\\pH=11.45[/tex]

Regards!


Related Questions

HELPPP PLEASEEEEE
Name the following alkane molecule:

Answers

Answer:

5–bromo–9–chlorodecane

Explanation:

To name the compound given above, the following must be obtained:

1. The longest continuous carbon chain. This gives the parent name of the compound.

2. The substituent group attached to the compound.

3. Position of the substituent group.

4. Combine the above to obtain the name.

Now, we shall determine the name of the compound as follow:

1. The longest continuous carbon chain is 10. Thus, the parent name of the compound is decane.

2. The substituent groups attached to the compound are:

I. Bromine (Br) => Bromo

II. Chlorine (Cl) => Chloro

3. The position of the substituent groups are:

I. Br => carbon 5

II. Cl => carbon 9

NOTE: numbering is done alphabetically.

4. Therefore, the name of the compound is:

5–bromo–9–chlorodecane

Answer:

A.

Explanation:

I chose this answer and it was correct ‍♀️

Write the precipitation reaction for cobalt(II) hydroxide in aqueous solution: Be sure to specify the state of each reactant and product.

Answers

Answer:

The equation for the precipitation reaction of cobalt (ii) hydroxide is given below:

CoSO₄ (aq) + NaOH (aq) ----> Co(OH)₂ (s) + Na₂SO₄ (aq)

Explanation:

Cobalt (ii) hydroxide is an inorganic compound consisting of cobalt (ii) ions, Co²+ and hydroxide ions, OH-. It is insoluble in water and the pure form known as the beta form is a pink-coloured solid. The impure form which incorporates other anions in its molecular structure is blue in colour and is ustable.

Cobalt (ii) hydroxide is formed as precipitate when an alkaline metallic hydroxide such as sodium hydroxide is mixed with an aqueous cobalt (ii) salt such as cobalt (ii) sulfate. The equation for the precipitation reaction of cobalt (ii) hydroxide is given below:

CoSO₄ (aq) + NaOH (aq) ----> Co(OH)₂ (s) + Na₂SO₄ (aq)

Being a basic hydroxide, cobalt (ii) hydroxide neutralizes acids to form cobalt (ii) salts and water. For example: Co(OH)₂ (s) + H₂SO₄ (aq) ---> CoSO₄ (aq) + H₂O

Thus, cobalt (ii) hydroxide is soluble in acids.

Cobalt(II) hydroxide is used mostly as a drying agent for paints, varnishes, and inks. It is also useful in the preparation of other cobalt compounds.

Phosphorus trichloride can be made by the following reaction: P4(s) 6Cl2(g) - 4) 4PCl3(l) What is the maximum amount of phosphorus trichloride that can be formed if 15 molecules of P4 are mixed with 42 molecules of chlorine

Answers

Answer:

48 molecules

Explanation:

From the given reaction:

[tex]\mathtt{P_4 + 6Cl_2\to 4PCl_3}[/tex]

i.e. 1 mole of Phosphorus react 6 moles of chlorine to yield 4 moles of PCl₃

This implies that for each P₄ molecule, we will require 6 molecules of Cl₂

We are provided with 15 molecules of P₄ and 42 molecules of Cl₂

Suppose we utilized the whole 15 molecules of P₄, we will require:

= 15 × 6 = 90 moles of Cl₂ which is not readily available except 42 are available.

If we utilized 42 molecules of Cl₂, we will require 42/6 = 7 molecules of P₄ which is readily available.

From this analysis, we can opine that Cl₂ serves as the limiting agent

P₄ : Cl₂ : PCl₃ = 1 : 6 : 4 = 7 : 42 : 48

It implies that only 48 molecules of phosphorus trichloride will be formed.

Question 3 0 / 1 point How many grams of carbon atoms are present in a sample of C3H8 if there are 4.10 moles of hydrogen atoms in the sample

Answers

Answer:

18.45 g of C

Explanation:

This is a problem of rules of three:

1 mol of C₃H₈ contains 3 moles of C and 8 moles of H

If 8 moles of H are contained in 1 mol of propane

4.10 moles of H are contained in (4.1 . 1) /8 = 0.5125 moles

Now, If 1 mol of propane contains 3 moles of C

0.5125 moles of propane may contain (0.5125 . 3) / 1 = 1.5375 moles of C

Let's convert the moles to mass:

1.5375 mol . 12 g /mol = 18.45 g

how many s electrons are there in potassium?​

Answers

Answer: 19

Explanation:

In order to write the Potassium electron configuration we first need to know the number of electrons for the K atom (there are 19 electrons). When we write the configuration we'll put all 19 electrons in orbitals around the nucleus of the Potassium atom.

the mass of a single potassium atom is 6.50×10-23 grams. How many potassium atoms would there be in 114 milligrams of potassium?

Answers

Answer:LOL

42

Explanation:

The mass of a single potassium atom is 6.50×10⁻²³ grams potassium atoms would be in 114 milligrams of potassium 17.53 ×10⁻²³.

What is an atom?

An atom is the most diminutive form of any chemical compound that takes part in the chemical reaction to form any product and it is equal to the one mole which is 2.303 ×10²³ moles of the Avogadros number.

To calculate the number of atoms we have,  6.50×10⁻²³ grams of potassium and the value of one particle is 2.303 ×10²³ moles,

           atoms =   6.50×10⁻²³  / 114 milligrams of potassium

          atoms of potassium = 17.53 ×10⁻²³. atoms.

Therefore, 17.53 ×10⁻²³.atoms are present if the mass of a single potassium atom is 6.50×10⁻²³ grams potassium atoms would there be in 114 milligrams of potassium.

Learn more about atoms, here:

https://brainly.com/question/15488332

#SPJ2

How many significant digits should be used to report the answer to each of the following calculations? (2.75518 + 9.01 + 3.3349) / (2.1)

Answers

Answer:

2

Explanation:

You write your answer with the same number of significant figures as the number with the smallest amount of figures, in this case, that number is 2.1 so your answer should be written with 2 significant figures.

The shielding of electrons gives rise to an effective nuclear charge, Zeff, which explains why boron is larger than oxygen. Estimate the approximate Zeff felt by a valence electron of boron and oxygen, respectively.
a. +5 and +8.
b. +3 and +6.
c. +5 and +6.
d. +3 and +8.
e. +1 and +4.

Answers

Answer:

b. +3 and +6.

Explanation:

Zeff = Z - S

The Z denotes the no of protons i.e. atomic number

S denotes the non-valence electrons

For boron,

the electronic configuration is 1s₂ 2s₂ 2p₄

Now  

Z = 5, S = 2

So,  

Zeff = 5-2

= +3

For O, the electronic configuration is 1s₂ 2s₂ 2p₄

So,  

Z = 8, S = 2

= 8-2

= +6

Hence, the second option is correct

A sample of gas with an initial volume of 9.35 L at a pressure of 784 torr and a temperature of 295 K is compressed to a volume of 2.84 L and warmed to a temperature of 310 K. What is the final pressure of the gas in atmospheres (atm)?
a. 4.97 atm.
b. 0.113 atm.
c. 5.95 atm.
d. 7.03x10^3 atm.

Answers

Answer:

D

Explanation:

P4 + NaOH + H2O——> PH3 + Na2HPO3
Balance given equation by oxidation no. Method

Answers

Answer:

P4 + 4NaOH + 2H2O → 2PH3 + 2Na2HPO3

Explanation:

A chemical equation is said to be balanced if the quantity of each type of atom in the reaction is the same on both the reactant and product sides. In a balanced chemical equation, the mass and the charge are both equal.

A chemical equation must balance according to the rule of conservation of mass. According to the rule, mass cannot be generated or removed during a chemical process.

Chemical equations must be balanced, which means that the atom types and numbers on both sides of the reaction arrow must match. Coefficients are the values added in front of formulas to balance equations; they multiply each atom in a formula.

Here the given equation is balanced as:

P₄ + 4NaOH + 2H₂O——> 2PH₃ + 2Na₂HPO₃

To know more about balanced equation, visit;

https://brainly.com/question/32997814

#SPJ6

How many photons are produced in a laser pulse of 0.203 J at 553 nm?

Answers

Answer:

8.59

10

17

Explanation:

You can start by figuring out the energy of a single photon of wavelength  

505 nm

=

505

10

9

 

m

.

To do that, use the equation

E

=

h

c

λ

Here

h

is Planck's constant, equal to  

6.626

10

34

.

J s

c

is the speed of light in a vacuum, usually given as  

3

10

8

.

m s

1

λ

is the wavelength of the photon, expressed in meters

Plug in your value to find--notice that the wavelength of the photon must be expressed in meters in order for it to work here.

E

=

6.626

10

34

 

J

s

3

10

8

m

s

1

505

10

9

m

E

=

3.936

10

19

 

J

So, you know that one photon of this wavelength has an energy of  

3.936

10

19

 

J

and that your laser pulse produces a total of  

0.338 J

of energy, so all that you need to do now is to find how many photons are needed to get the energy output given to you.

0.338

J

1 photon

3.936

10

19

J

=

8.59

10

17

 

photons

−−−−−−−−−−−−−−−−−

 

The answer is rounded to three sig figs.

Draw the structural formula for both of these alcohols:
2,3, 4-trimethyl, 3-heptanol
4-ethyl, 4-octanol

Answers

Answer:

Check the image above

explanation:

When naming organic compounds based on IUPAC; we take note of functional group, position of functional group.

In 2,3,4-trimethyl-3-heptanol, the functional group is hydroxyl group ( OH ). It is on position 3 (2,3,4-trimethyl-3-heptanol. Then we put it on the third carbon. Another functional group is methyl group, with three positions, 2, 3, and 4.

In 4-ethyl-4-octanol, the functional group is hydroxyl group ( OH ) which is in position 4 on the fourth carbon. Another functional group is ethyl group in position 4 on the fourth carbon. In this case, the functional groups that have same position, are put on that same carbon.

given two equations representing reactions: which type of reaction is represented by each of these equations?

Answers

Answer:

Equation 1 - nuclear fission

Equation 2 - nuclear fusion

Explanation:

Nuclear fission is a reaction in which a large nucleus is split into smaller nuclei when it is bombarded by neutrons. The process produces more neutrons to continue the chain reaction. This is clearly depicted in equation 1 as shown in the question.

Nuclear fusion is a reaction in which two light nuclei combine in order to form a larger nuclei. This is clearly depicted in equation 2 as shown in the question.

In the first reaction, a neutron is released, and in the second a helium atom is released. The given two equations represent nuclear fission and fusion.

What are nuclear reactions?

A nuclear reaction is a reaction that involves the nuclei of the atom and the absorption and release of energy. In the first reaction, a big nucleus is split by the neutron bombardment into smaller nuclei.

In the second reaction the process of nuclear fusion, two nuclei combine into a single larger nucleus that is shown as:

₁¹H+ ²₁H → ³₂He

Therefore, nuclear fission and fusion are represented by each of these equations.

Learn more about nuclear reactions here:

https://brainly.com/question/16526663

#SPJ5

The decomposition of hydrogen peroxide was studied, and the following data were obtained at a particular temperature.Time (s) [H2O2] (mol/L)0 1.00120 ± 1 0.91300 ± 1 0.78600 ± 1 0.591200 ± 1 0.371800 ± 1 0.222400 ± 1 0.133000 ± 1 0.0823600 ± 1 0.050 Assuming that the rate= -delta [H2O2]/delta t determine the rate law, integrated rate law, and the value of the rate constant. Calculate [H2O2] at 4000. s after the start of the reaction.

Answers

Answer:

Explanation:

From the graphical diagram attached below; we can see the relationship between the concentration of [tex]H_2O_2[/tex] which declines exponentially in relation to the time and it obeys the equation: [tex]\mathtt{y = 0.9951 e^{-8\times 10^{-4}x}}[/tex]

This relates to the 1st order reaction rate, whereby:

The integrated rate law[tex]\mathtt{ [A] = [A]_o e^{-kt}}[/tex]

here:

[A] = reactant concentration at time (t)

[A]_o = initial concentration for the reactant

k = rate constant

As such, the order of the reaction is the first order

Rate constant [tex]\mathtt{k = 8\times 10^{-4} {s^{-1}}}[/tex]

Rate law [tex]\mathtt{= k[H_2O_2]}[/tex]

The integrated rate law [tex]\mathtt{[H_2O_2] = [H_2O_2]_oe^{-(8*10^{-4})t}}[/tex]

From the given table:

the initial concentration of [tex]H_2O_2[/tex] = 1.00 M

We can determine the concentration of the reactant at 4000s by using the formula:

[tex]\mathtt{[H_2O_2] = [H_2O_2]_oe^{-8*10^{-4}(t)}}[/tex]

[tex]\mathtt{[H_2O_2] = (1.00\ M)*e^{-8*10^{-4}(4000)\ s}}[/tex]

[tex]\mathtt{[H_2O_2] =0.0407 \ M}[/tex]

Finally, at 4000s: the average rate is:

[tex]\mathtt{= (8*10^{-4} \ s^{-1})(4000 \ s) }\\ \\ \mathtt{ = 3.256 \times 10^{-5} \ M/s}[/tex]

What was one idea Dalton taught about atoms?

Answers

Explanation:

All atoms of one type were identical in mass and properties.

Look at pictures and help please

Answers

Answer: In order to increase the rate of reaction between hydrochloric acid and sugar increase the concentration of hydrochloric acid to 2 M because greater concentration results in more collision between the reactants.

Explanation:

More is the concentration of reactant molecules more will be the number of collisions between their molecules. As a result, more readily the products will be formed.

Hence, for the given reaction when concentration of HCl is increased then there will be increase in the number of collisions between reactants.

Thus, we can conclude that in order to increase the rate of reaction between hydrochloric acid and sugar increase the concentration of hydrochloric acid to 2 M because greater concentration results in more collision between the reactants.

Question on the image

Answers

Answer: The mass of carbon dioxide required is 308 g

Explanation:

The number of moles is defined as the ratio of the mass of a substance to its molar mass.

The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)

Given mass of octane = 100.0 g

Molar mass of octane = 114.23 g/mol

Putting values in equation 1, we get:

[tex]\text{Moles of octane}=\frac{100.0g}{114.23g/mol}=0.875mol[/tex]

For the given chemical reaction:

[tex]2C_8H_{18}+25O_2\rightarrow 16CO_2+18H_2O[/tex]

By the stoichiometry of the reaction:

2 moles of octane produces 16 moles of carbon dioxide

So, 0.875 moles of octane will produce = [tex]\frac{16}{2}\times 0.875=7mol[/tex] of carbon dioxide

Molar mass of carbon dioxide = 44 g/mol

Plugging values in equation 1:

[tex]\text{Mass of carbon dioxide}=(7mol\times 44g/mol)=308g[/tex]

Hence, the mass of carbon dioxide required is 308 g

sound waves? like what they do.

Answers

Answer:

A sound wave is the pattern of disturbance caused by the movement of energy traveling through a medium (such as air, water, or any other liquid or solid matter) as it propagates away from the source of the sound. The source is some object that causes a vibration, such as a ringing telephone, or a person's vocal chords.

HEY. HOPE THIS HELPS♡

A 1.375 g sample of mannitol, a sugar found in seaweed, is burned completely in oxygen to give 1.993 g of carbon dioxide and 0.9519 g of water. The empirical formula of mannitol is

Answers

Answer:

[tex]C_3H_7O_3[/tex]

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to infer that the empirical formula of mannitol contains carbon, hydrogen and oxygen, so that the first step is to calculate the moles of C and H contained in the CO2 and H2O, respectively, as the only sources of these two elements in the formula:

[tex]n_C=1.993gCO_2*\frac{1molCO_2}{44.01gCO_2}*\frac{1molC}{1molCO_2} =0.0453molC\\\\n_H=0.9519gH_2O*\frac{1molH_2O}{18.02gH_2O}*\frac{2molH}{1molH_2O} =0.106molH[/tex]

Next, we calculate the grams and moles of O by subtracting the mass of C and H from the mass of the sample:

[tex]m_O=1.375g-0.0453molC*\frac{12gC}{1molC}-0.106molH*\frac{1.01gH}{1molH}=0.724gO\\\\n_O=0.724gO*\frac{1molO}{16.0gO} =0.0453molO[/tex]

Finally, we divide the moles of C, H and O by 0.0453 as the fewest moles of both C and O to find the mole ratios in the formula:

[tex]C:\frac{0.0453mol}{0.0453mol} =1\\\\H:\frac{0.106mol}{0.0453mol} =2.34\\\\O:\frac{0.0453mol}{0.0453mol} =1[/tex]

To get:

[tex]CH_{2.34}O[/tex]

Which must be multiplied by 3 to get whole numbers for all the subscripts, and therefore obtain:

[tex]C_3H_7O_3[/tex]

Regards!

Beer's Law states that A=ebc, where A is the absorbance, ε is the molar absorptivity of the solute, b is the path length, and c is the concentration. Identify the experimental evidence from the activity that you have for the dependence of absorbance on each variable

The evidence for the dependence of absorbance on the variable ε is:_________

a. increasing the cuvette width increases the absorbance.
b. changing the compound changes the absorbance behavior.
c. adding more water decreases the absorbance.

Answers

Answer:

b. changing the compound changes the absorbance behavior.

Explanation:

Option a) would be akin to modifying the path length, b.Option b) would involve using a different solute, as such, there would be another molar absortivity, ε.Option c) would decrease the concentration (c) of the solute, which would explain why the absorbance would decrease as well.

3. How many electrons are in the M shell?

Answers

Answer:

i believe the answer is D: 18

Explanation:

Answer:

18

M shell can actually hold 18 electron as you move higher atomic number

The largest number of stable nuclei have an ________ number of protons and an ________ number of neutrons.

Answers

Answer:

did it give you answers to in blanks

What is one way in which a field investigation can differ from a classroom or laboratory experiment?

Answers

Answer:

□In field investigations, you are usually working with much larger animals than in the lab. In field investigations, it is much more difficult to separate your control and experimental groups.

There are many ways in which a field  experiment can differ form of a classroom or a laboratory experiment,  one of which can be the environmental condition.

What is a field experiment?

 A field experiment Is an experiment  which is performed in practically Outside the classroom or a laboratory in live situtations .

Environmental factors may deter the results  of a field experiment or  may alter the physical conditions of the object, For example  an anhydrous substance may become  hygroscopic, Which may  Alter the result of the field experiment.

  Hence,  field experiment can differ from  a classroom or a laboratory experiment  due to environmental conditions .

Learn more about laboratory Experiment.

https://brainly.com/question/13142627

#SPJ2

g a commercial product for treating injuries contains 35.0 g of MgSO4 in one bag and 250 mL of water in a seperate bag. When the bags are broken and their contents mixed, the temperature of the system changes. Calculate this temperature change

Answers

Answer:

he a real G

Explanation:

og tripple og

Plss help me solve question 7
Thank you.

Answers

Answer:

4- ethyl- 6-methylocta- 1,2,5- triene

Explanation:

See attached. Please give me brainliest I worked hard. ;(

In the picture this is my last question pls.

Answers

Answer:

Chromosomes and I think its too many

Explanation:

What is the solute and solvent in a solution of salt water

Answers

Answer:

The solute is salt and the solvent is water

Explain:

Because salt is a component the dissolves in the solvent

A certain shade of blue has a frequency of 7.28×1014 Hz.
What is the energy of exactly one photon of this light? Planck's constant is ℎ=6.626×10−34 J⋅s.

Answers

Explanation:

the enerfy of of one photon of this light is 4.85x10^-19 J

E= 6.63 x 10^-34 J/S x 7.32 x10^14 S ^-1

E= 4.85x10^-19 J

Using the periodic table,
choose the more reactive nonmetal. Br or as

Answers

Answer:

Br

Explanation:

because bromine is more reactive as reactivity increases on moving from left to right in p-block. hope this make sense :)

20)
Which substance is an acid?


A)
Ba(OH)2

B)
CH3COOCH3

C)
H3PO4

D)
NaCl

help

Answers

Answer:

C.

Explanation:

Also, please help me in my questions tab if you can! Thank you so much

Other Questions
help please lol soon what is the story of Romeo and Juliet Find the distance between the points given.(-3,-4) and (0,0) what is the process of transformation?infecting bacteria with bacteriophagesadding foreign DNA to a bacterial cellcopying foreign DNA into RNAcausing mutations in viral genetic material What is the answer to 24 + y = 41 At a BAC of___blackouts are common.A. 0.09B. 0.13C. 0.20 There are 6 blue marbles, 3 red marbles, and 5 yellow marbles in a bag. What is the probability of selecting a blue or red marble on the first draw? I need it in a fraction, decimal, and a percent HURRY PLS Construct a concept map on the difference between meiosis and mitosis using the given descriptions below. A restaurant with 25 tables has 4 tables by the window. Parties are seated randomly at the tables as they come in.What is the probability that the first 3 parties of the night are all seated at window seats? Find the area of the triangle, WILL GIVE BRAINLIEST Sara, a 14-year-old, has come to the office for her school physical. She is very remote, moody, and unwilling to answer any questions you ask her as part of her physical exam. She seems to have changed a great deal in the past year, and is thinner, more unkempt, and lethargic. You notice also that her mother is constantly badgering her and rolling her eyes in exasperation at her lack of cooperation.What could you do to facilitate the examination and improve communication with Sara?What possible problems could Sara be experiencing?What should you do about the concerns that you have for Sara? 4(x + 3) + 2x in the simplest form A consumer has $180 in monthly income to spend on two goods, D and G, where D is on the y-axis. The price of good D, PD is $6, and the marginal rate of transformation is -2. How many units of good G can be purchased if all income is used to purchase good G I FRICKING CRYING RN I JUST FINISHED "BLOOD BANK" AND I AM IN TEARS write a letter to your aunt telling her how you spent your last holiday What was the primary reason for the fall of the Roman Empire? ABDIf mZACD = 70, then mZBCD = [? ] Brainliest!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! What is an inscribed polygon is being constructed What is an atom trying to dowhen it combines with otheratoms?A. produce a reaction TingB. change state of matterC. become less stableD. become stable