CHEMISTRY COLLEGE

Calculate the pH of a solution prepared by adding 20.0 mL of 0.100 M HCl to 80.0 mL of a buffer that is comprised of 0.25 M C2H5NH2 and 0.25 M C2H5NH3Cl. Kb of C2H5NH2 = 9.5 x 10-4.

Answers

Answer 1

Answer:

Answer: The pH of resulting solution is 10.893

Explanation:

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}* 1000}{\text{Volume of solution (in mL)}}$

For ethylamine:

Molarity of ethylamine solution = 0.25 M

Volume of solution = 80 mL

Putting values in above equation, we get:

$0.25M=\frac{\text{Moles of ethylamine}* 1000}{80mL}\n\n\text{Moles of ethylamine}=(0.25* 80)/(1000)=0.02mol$

For HCl:

Molarity of HCl = 0.100 M

Volume of solution = 20.0 mL

Putting values in above equation, we get:

$0.100M=\frac{\text{Moles of HCl}* 1000}{20.0mL}\n\n\text{Moles of HCl}=(0.100* 20)/(1000)=0.002mol$

For $C_2H_5NH_3Cl$ :

Molarity of $C_2H_5NH_3Cl$ solution = 0.25 M

Volume of solution = 80 mL

Putting values in above equation, we get:

$0.25M=\frac{\text{Moles of }C_2H_5NH_3Cl* 1000}{80mL}\n\n\text{Moles of }=(0.25* 80)/(1000)=0.02mol$

The chemical reaction for ethylamine and HCl follows the equation:

$C_2H_5NH_2+HCl\rightarrow C_2H_5NH_3Cl$

Initial: 0.02 0.002 0.02

Final: 0.018 - 0.022

Volume of solution = 20.0 + 80.0 = 100 mL = 0.100 L (Conversion factor: 1 L = 1000 mL)

To calculate the pOH of basic buffer, we use the equation given by Henderson Hasselbalch:

$pOH=pK_b+\log(([salt])/([base]))$

$pOH=pK_b+\log(([C_2H_5NH_3Cl])/([C_2H_5NH_2]))$

We are given:

$pK_b$ = negative logarithm of base dissociation constant of ethylamine = $-\log(9.5* 10^(-4))=3.02$

$[C_2H_5NH_3Cl]=(0.022)/(0.100)$

$[C_2H_5NH_2]=(0.018)/(0.100)$

pOH = ?

Putting values in above equation, we get:

$pOH=3.02+\log((0.022/0.100)/(0.018/0.100))\n\npOH=3.107$

To calculate pH of the solution, we use the equation:

$pH+pOH=14\npH=14-3.107=10.893$

Hence, the pH of the solution is 10.893

Answer 2

Answer:

The pH of the solution is 10.9

Data;

Volume of buffer = 80mL
Volume of HCL = 20.0mL
conc. of C2H5NH2 = 0.25M
conc. of C2H5NH3Cl = 0.25
Kb of C2H5NH2 = 9.5*10^-4

pH of a Solution

The pH of buffer can be calculated by using Henderson-Hasselbalch's equation

$pOH = _pKb+ log ([salt])/([base])$

The initial moles of salt present is calculated as

$0.25 * 80*10^-^3 = 0.02mmoles$

The initial moles of base present is calculated as

$0.25*80*10^-^3 = 20mmoles$

On adding HCl the following reaction will occurs

$C_2H_5NH_2 + HCl \to C_2H_5NH_3Cl$

This will lead to formation of extra moles of salt that is equal to moles of acid added and eventually lead to decrease in number of moles of base by equal measure.

Moles of HCl added is

$moles of HCL= 0.1 * 20 * 10^-^3 = 2mmoles$

Adding the value

Moles of salt present = 20 + 2 = 22mmoles

Subtracting the value

Moles of base left = 20-2 = 18mmoles

Now using Henderson-Hasselbalch's equation we can calculate the pOH of solution

$pKb = -logKb = -log (9.5*10^-^4) = 3.02$

The pOH of the base can be calculated as

$pOH = 3.02 + log ((22)/(18)) = 3.107$

Using the above, we can solve for the pH of the solution.

$pH = 14 - pOH = 10.893$

The pH of the solution is 10.9

Learn more on pH of a solution using Henderson-Hasselbalch equation here;

brainly.com/question/13557815

Related Questions

In both industry and research there are often times when one particular component of a mixture needs to be separated from a solution. Maybe it is a rare metal that is dissolved in a mixture of minerals. Maybe it is a particular protein from lysed plant cells. If the desired component is volatile, distillation could be used. But if the goal is to separate ions in solution, fractional precipitation is preferred.a. Trueb. False
A chemist prepares a solution of potassium permanganate (KMnO4) by measuring out 3.8 umol of potassium permanganate into a 100 mL volumetric flask and filling the flask to the mark with water. Calculate the concentration in mol/L of the chemist's potassium permanganate solution. Round your answer to 2 significant digits. x 5 ? Explanation Check
Calculate the mass percent of oxygen in KMnO4.
Animal fats tend to be _______________ with hydrogen atoms. (fifth paragraph of this sub-section
Based on your knowledge of waves and fider optic cables, which type of wave would be found in a fiber optic cable? Explain how you got the answer and i will mark brainliest!!!! Thank you sooooo much!

In the important industrial process for producing ammonia (the Haber Process), the overall reaction is: N2(g) + 3H2(g) → 2NH3(g) + 24,000 calories A yield of ammonia, NH3, of approximately 98% can be obtained at 200°C and 1,000 atmospheres of pressure. How many grams of N2 must react to form 1.7 grams of ammonia?

Answers

Answer:

Mass of N2 required = 1.429 g

Explanation:

The given reaction is:

N2(g) + 3H2(g) → 2NH3(g)

Mass of NH3 formed = 1.7 g

Molar mass of NH3 = 17 g/mol

$Moles(NH3) = (Mass)/(Molar mass) = (1.7)/(17) = 0. 1$

Based on the reaction stoichiometry:

1 mole of N2 forms 2 moles of NH3

Therefore, moles of N2 required to produce 0.1 moles of NH3 is:

$= (1 mole(N2)*0.1moles(NH3))/(2 moles(NH3)) =0.05 moles(N2)$

Molar mass of N2 = 28 g/mol

Mass of N2 required = moles*molar mass = 0.05*28 = 1.4 g

This is the theoretical mass corresponding to a 100% yield. Since the yield of NH3 is 98%, the corresponding mass of N2 required would be:

$=(1.4)/(0.98) =1.429 g$

28g N2/(17 x 2 x 0.98) g NH3

1.7 g NH3 x 28g N2/(17 x 2 x 0.98) g NH3 =

47.6 / 33.32 = 1.43 g N2

Identify each element below, and give the symbols of the other elements in its group. a. [Ar] 4s23d104p4
b. [Xe] 6s24f145d2
c. [Ar] 4s23d5.

Answers

Answer:

Explanation:

the electron configuration is defined as the distribution of electrons of an atom or molecule in atomic or molecular orbitals. It is

used to describe the orbitals of an atom in its ground state

The valence electrons, electrons in the outermost shell, can be used to know the chemical property

Chemical Name of the Element: Selenium

Chemical Symbol: Se

Group it belong in periodic table:6A

Other Element in the same group:tellurium(Te),,sulfur(S)

atomic number = 34

Selenium is a chemical element that has symbol Se It is a nonmetal which is usually classified as metalloid with properties that are intermediate between the elements above and below in the periodic table.

b)Chemical Name of the Element:Hafnium

Chemical Symbol: Hf

Group it belong in periodic table:4B

Other Element in the same group: Titanium( Ti )Rutherfordium

atomic number: 72

Hafnium is a solid at room temperature.

c)Chemical Name of the Element: Manganese

Chemical Symbol:Mg

Group it belong in periodic table:Mn

Other Element in the same group:Bohrium(Bh) ,Technetium(Tc)

What is the partial pressure of nitrogen in a container that contains 3.96mol of oxygen, 7.49 mol of nitrogen and 1.19 mol of carbon dioxide when the total pressure is 563 mmHg?

Answers

Answer:

333.6 atm

Explanation:

The following data were obtained from the question:

Mole of O2 (nO2) = 3.96 moles

Mole of N2 (nN2) = 7.49 moles

Mole of CO2 (nCO2) = 1.19 moles

Total pressure = 563 mmHg

Partial pressure of N2 =..?

Next, we shall determine the total number of mole in the container.

This can be obtained as follow:

Mole of O2 (nO2) = 3.96 moles

Mole of N2 (nN2) = 7.49 moles

Mole of CO2 (nCO2) = 1.19 moles

Total mole =?

Total mole = nO2 + nN2 + nCO2

Total mole = 3.96 + 7.49 + 1.19

Total mole = 12.64 moles

Next, we shall determine the mole fraction of N2.

This can be obtained as follow:

Mole fraction = mole of substance/total mole

Mole of N2 (nN2) = 7.49 moles

Total mole = 12.64 moles

Mole fraction of N2 =?

Mole fraction of N2 = 7.49/12.64

Finally, we shall determine the partial pressure of N2.

This can be obtained as follow:

Mole fraction of N2 = 7.49/12.64

Total pressure = 563 mmHg

Partial pressure of N2 =..?

Partial pressure = mole fraction x total pressure

Partial pressure of N2 = 7.49/12.64 x 563

Partial pressure of N2 = 333.6 atm

The, the partial pressure of nitrogen, N2 is 333.6 atm

Calculate the molar mass of each compound given below. c4h4

Answers

When asked to find molar mass, we first need to calculate the total number of atoms of each element in the compound.

In $C_(4) H_(4)$ , we see that there are 4 Carbons and 4 Hydrogens.

We then need to look up the atomic mass of each of these elements, which is found on the periodic table.

For carbon, the atomic mass is 12.01g
For hydrogen, the atomic mass is 1.008g

Then we multiply the number of atoms in the element by the atomic mass of the element:

C: $4*12.01g=48.04g$
H: $4*1.008g=4.032g$

And then we need to add these two values together to get the molar mass of the compound:

$48.04g+4.032g=52.072g$

So now we know that the molar mass of $C_(4) H_(4)$ is 52.072g.

What volume of 0.335 molar hydrochloricacid solution would be required to neutral-
ize completely 39 mL of 0.137 molar sodium
hydroxide solution?
Answer in units of mL.

Answers

The volume of 0.335 molar hydrochloric acid solution would be required to neutralize completely 39 mL of 0.137 molar sodium hydroxide solution is 15.95mL.

How to calculate volume?

The volume of a substance in a neutralization reaction can be calculated using the following formula;

CaVa = CbVb

Where;

Ca = concentration of acid
Va = volume of acid
Cb = concentration of base
Vb = volume of base

According to this question, 0.335 molar hydrochloric acid solution would be required to neutralize completely 39 mL of 0.137 molar sodium hydroxide solution.

0.335 × Va = 39 × 0.137

0.335Va = 5.343

Va = 15.95mL

Learn more about volume at: brainly.com/question/15195026

#SPJ1

Nitrogen dioxide is one of the many oxides of nitrogen (often collectively called "") that are of interest to atmospheric chemistry. It can react with itself to form another form of , dinitrogen tetroxide. A chemical engineer studying this reaction fills a flask with of nitrogen dioxide gas. When the mixture has come to equilibrium he determines that it contains of nitrogen dioxide gas. The engineer then adds another of nitrogen dioxide, and allows the mixture to come to equilibrium again. Calculate the pressure of dinitrogen tetroxide after equilibrium is reached the second time. Round your answer to significant digits.

Answers

Answer:

Explanation:

idek

Other Questions

Sodium phosphate and calcium chloride react to form sodium chloride and calcium phosphate. If you have 379.4 grams of calcium chloride and an excess of sodium phosphate, how much calcium phosphate can you make?

In the equilibrium system described by: PO43-(aq) + H2O(1) = HPO42-(aq) + OH-(aq) Brønsted-Lowry theory would designate: A) PO43- and H20 as the bases B) H20 and OH as a conjugate pair C) HPO42- and OH"" as the acids D) HPO42- and H20 as a conjugate pair E) PO43-as amphiprotic

What makes physical change a physical change and a chemical change a chemical change

At 1 atm, an unknown sample melts at 49.9 °C and boils at 209.5 °C. If the temperature is 0°C, what is the state of matter for the sample?