A buffer is prepared containing 0.75 M NH3 and 0.20 M NH4 . Calculate the pH of the buffer using the Kb for NH3. g

Answers

Answer 1

Answer:

pH=8.676

Explanation:

Given:

0.75 M [tex]NH_{3}[/tex]

0.20 M [tex]NH_{4}[/tex]

The objective is to calculate the pH of the buffer using the kb for [tex]NH_3[/tex]

Formula used:

[tex]pOH=pka+log\frac{[salt]}{[base]}\\[/tex]

pH=14-pOH

Solution:

On substituting salt=0.75 and base=0.20 in the formula

[tex]pOH=-log(1.77*10^{-5})+log\frac{0.75}{0.20}\\ =4.75+0.5740\\ =5.324[/tex]

pH=14-pOH

On substituting the pOH value in the above expression,

pH=14-5.324

Therefore,

pH=8.676


Related Questions

Acetic acid and water react to from hydronium cation and acetate anion, like this: HCH3CO2 (aq) + H2O (I) → H3O+(aq) + Ch3CO2-(aq)Imagine 226. mmol of CH3CO2- are added to a flask containing a mixture of HCH3CO2, H2O, H3O + and CH3CO2- at equilibrium, and then answer the following questions. 1. What is the rate of the forward reaction before any HCH3CO2 has been removed from the flask? a. Zero.b. Greater than zero, but less than the rate of the reverse reaction. c. Greater than zero, and equal to the rate of the reverse reaction. d. Greater than zero, and greater than the rate of the reverse reaction. 2. What is the rate of the forward reaction just after the HCH3CO2 has been removed from the flask?a. Zero.b. Greater than zero, but less than the rate of the reverse reaction. c. Greater than zero, and equal to the rate of the reverse reaction. d. Greater than zero, and greater than the rate of the reverse reaction.3. What is the rate of the forward reaction when the system has again reached equilibrium?a. Zero.b. Greater than zero, but less than the rate of the reverse reaction. c. Greater than zero, and equal to the rate of the reverse reaction. d. Greater than zero, and greater than the rate of the reverse reaction.

Answers

Answer:

1) Greater than zero, and equal to the rate of the reverse reaction

2) Greater than zero, but less than the rate of the reverse reaction

3) Greater than zero, and equal to the rate of the reverse reaction

Explanation:

A reaction system is said to be in equilibrium when the rate of forward reaction is equal to the rate of reverse reaction.

Before we remove HCH3CO2 from the system, the system was in equilibrium. Recall that when a system is in equilibrium, the rate of forward reaction is equal to the rate of reverse reaction. The rate of reaction is greater than zero because products are being formed as the reactants interact with each other.

When HCH3CO2 is removed from the system, the equilibrium position shifts towards the left hand side hence the rate of reverse reaction is greater than the rate of forward reaction.

When the system attains equilibrium again, the rates of forward and reverse reaction become equal.

Suppose a 48. L reaction vessel is filled with 1.6 mol of Br2 and 1.6 mol of OCl2. What can you say about the composition of the mixture in the vessel at equilibrium

Answers

Answer:

There will be very little of BrOCl BrCl

Explanation:

Based on the equilibrium:

Br2(g) + OCl2(g) ⇄ BrOCl(g) + BrCl(g)

The equilibrium constant, Kc, is:

Kc = 1.58x10⁻⁵ = [BrOCl] [BrCl] / [Br2] [OCl2]

As Kc is <<< 1, in equilibrium, the concentration of products will remain lower regard to the concentration of the reactants. That means, right answer is;

There will be very little of BrOCl BrCl

All --- is a good conductor of heat​

Answers

all metals is a good conductor of heat

Calculate the mass percent of carbon in the following molecule: Mn3[Mn(CO)4]3

Answers

Answer:

21.63 %

Explanation:

The molar mass of Mn₃[Mn(CO)₄]₃ is 665.64 g/mol.

Let's assume we have 1 mol of Mn₃[Mn(CO)₄]₃, if that were the case then we would have 665.64 grams.

There are 12 C moles per Mn₃[Mn(CO)₄]₃, with that in mind we calculate the weight of 12 C moles:

12 mol C * 12 g/mol = 144 g

Finally we calculate the mass percent of carbon:

144 g / 665.64 g * 100% = 21.63 %

3. A 3.455-g sample of a mixture was analyzed for barium ion by adding a small excess of sulfuric acid to an aqueous solution of the sample. The resultant reaction produced a precipitate of barium sulfate, which was collected by filtration, washed, dried, and weighed. If 0.2815 g of barium sulfate was obtained, what was the mass percentage of barium in the sample

Answers

Answer:

[tex]Ba\ percentage\ in\ Mass=4.8\%[/tex]

Explanation:

From the question we are told that:

Mass of mixture [tex]m=3.455g[/tex]

Mass of Barium [tex]m_b=0.2815g[/tex]

Equation of Reaction is given as

[tex]Ba2+ + H2SO4 => BaSO4 + 2 H+[/tex]

Generally the equation for Moles of Barium  is mathematically given by

Since

 [tex]Moles of Ba^{2+} = Moles of BaSO_4[/tex]

Therefore

 [tex]Moles of Ba^{2+} = \frac{mass}{molar mass of BaSO4}[/tex]  

 [tex]Moles of Ba^{2+} = \frac{0.2815}{233.39}= 0.0012061 mol[/tex]

Generally the equation for Mass of Barium  is mathematically given by

 [tex]Mass\ of\ Ba^{2+} = Moles * Molar mass of Ba^{2+}[/tex]  

 [tex]Mass\ of\ Ba^{2+} = 0.0012061 * 137.33 = 0.1656 g[/tex]

Therefore

 [tex]Ba\ percentage\ in\ Mass = mass of Ba^{2+}/mass of sample * 100%[/tex]    

 [tex]Ba\ percentage\ in\ Mass= \frac{0.1656}{ 3.455 }* 100%[/tex]

 [tex]Ba\ percentage\ in\ Mass=4.8\%[/tex]

a laser emits light with a frequency of 4.69 x 10 to the 14th power s - 1 calculate the wavelength of this light.

Answers

Answer:

6.40x10^-7

Explanation:

answer with work is attached.

Which of the following elements is the largest in size
a. O
b. He
c. K
d. H

Answers

Answer:

C. K

i took this class before

Answer: The largest element is K

Explanation: As K has the largest radius among O,He and H

Consider the balanced chemical equation below.

3 A ⟶ C + 4 D

How many moles of D would be produced if 9 moles of A were used?

Answers

hope the picture above helps :)

Assign priorities in the following set of substituents according to Cahn-Ingold-Prelog rules.
-OCH3 -Br -Cl -CH2OH
А B C D
(Provide your ranking through a string like abcd, starting with the one with the highest priority).

Answers

Answer:

Assign priorities in the following set of substituents according to Cahn-Ingold-Prelog rules.

-OCH3 -Br -Cl -CH2OH

Explanation:

To give priorities for the substituents that are attached to chiral carbon and  to assign either R or S-configuration the following rules were proposed:

1. The atom with the highest atomic number is given first priority.

2. If the Groups attached to chiral carbon are having the same first atom, then check for the atomic number of the second atom.

Among the given groups,

-Br has the highest atomic number, so it is given first priority.

Then, -Cl.

Then, -OCH3

and the last one is -CH2OH.

Hence, the order is :

BCAD.

Calculate the solubility (in mol/L) of Fe(OH)3 (Ksp = 4.0 x 10^-38) in each of the following situations:
(A) Pure water (assume that the pH is 7.0 and remains constant).
(B) A solution buffered at pH = 5.0.
(C) A solution buffered at pH = 11.0.

Answers

Answer:

(A) 1.962x10^-10 M solubility in pure water

(B) 4.0 x 10^-33 M solubility

(C) 4.0 x 10^-27 M solubility

Explanation:

(A) Fe(OH)3 would give (Fe3+) and (3OH-)

Ksp = [Fe^3+][OH-]^3 = 4.0 x 10^-38

Let y = [Fe^3+]

Let 3y = [OH-]

4x10^-38 = (y)(3y)^3

4x10^-38 = 27y^4

y^4 = 4x10^-38 ÷ 27

y^4 = 1.481 x 10^-39

y = 1.962x10^-10 M solubility in pure water

(B) pH = 5.0

5.0 = - log [OH-]

-5.0 = log [OH-]

[OH-] = 10^-5.0 =  1.0 x 10^-5 M

So, Ksp = [Fe^3+][OH-]^3 = 4.0 x 10^-38

[Fe^3+][1.0 x 10^-5] = 4.0 x 10^-38

[Fe^3+] = 4.0 x 10^-38 ÷ 1.0 x 10^-5

= 4.0 x 10^-33 M solubility

(C) pH = 11.0

11.0 = - log [OH-]

-11.0 = log [OH-]

[OH-] = 10^-11.0 =  1.0 x 10^-11 M

So, Ksp = [Fe^3+][OH-]^3 = 4.0 x 10^-38

[Fe^3+][1.0 x 10^-11] = 4.0 x 10^-38

[Fe^3+] = 4.0 x 10^-38 ÷ 1.0 x 10^-11

= 4.0 x 10^-27 M solubility

A ball is thrown straight up into the air with a speed of 21 m/s. If the ball has a mass of 0.1 kg, how high does the ball go? Acceleration due to gravity is g = 9.8 m/s^2

Answers

Answer:

answer = 22.5m

Explanation:

using

[tex]s = \frac{ {v}^{2} - {4}^{2} }{2a} [/tex]

s= (0²-21²)/2(-9.8)

s= -441/19.6

s= 22.5m

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According to the kinetic-molecular theory, gas molecules have
ANSWER:
Part
A. Less energy than molecules of a solid.
B. strong interactions between molecules.
C. little distance between molecule
D. weak interactions between molecules.

Answers

Answer:

The choose ( D )

weak interactions between molecules.

Answer:

Explanation:

el     a  

Given 0.60 mol CO2, 0.30 mol CO, and 0.10 mol H20, what is the partial pressure of the CO if the total pressure of the mixture was 0.80 atm?

Answers

Answer:

Explanation:

/ means divided by

* means multiply

1. formula is

partial pressure = no of moles(gas 1)/ no of moles(total)

0.30 mol CO/0.60 mol CO2 + 0.30 mol CO + 0.10 mol H20 ->

.3/(.6+.3+.1) =

.3/1 =

.3 =

partial pressure of CO

2.

.3 * .8 atm = .24

khanacademy

quizlet

The partial pressure of the CO is 0.24 atm if the total pressure of the mixture was 0.80 atm.

Dalton's Law of Partial pressure

Dalton's Law of partial pressure states that the total pressure exerted by non reacting gaseous mixture at a constant temperature and given volume is equal to the sum of partial pressure of all gases.

Dalton's Law of partial pressure using mole fraction of gas

Partial pressure of carbon monoxide (CO) = Mole fraction of carbon monoxide (CO) × Total pressure

Now, we have to find the first mole fraction of CO

Mole fraction of carbon monoxide (CO) = [tex]\frac{\text{moles of solute}}{\text{total moles of solute}}[/tex]

                                                                  = [tex]\frac{\text{moles of CO}}{\text{moles of CO}_2 + \text{moles of CO} + \text{moles of H}_{2}O}[/tex]

                                                                  = [tex]\frac{0.30}{0.60 + 0.30 + 0.10}[/tex]

                                                                  = [tex]\frac{0.30}{1}[/tex]

                                                                  = 0.3

Now, put the value in above equation, we get that

Partial pressure of carbon monoxide (CO)

= Mole fraction of carbon monoxide (CO) × Total pressure

= 0.3 × 0.8

= 0.24 atm

Thus, the partial pressure of the CO is 0.24 atm is the total pressure of the mixture was 0.80 atm.

Learn more about the Dalton's Law of partial Pressure here: https://brainly.com/question/14119417

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Enough of a monoprotic acid is dissolved in water to produce a 1.211.21 M solution. The pH of the resulting solution is 2.882.88 . Calculate the Ka for the acid.

Answers

Answer:

1.44 × 10⁻⁶

Explanation:

Step 1: Given data

Concentration of the acid (Ca): 1.21 MpH of the solution: 2.88

Step 2: Calculate the concentration of H⁺ ions

We will use the definition of pH.

pH = -log [H⁺]

[H⁺] = antilog -pH = antilog -2.88 = 1.32 × 10⁻³ M

Step 3: Calculate the acid dissociation constant of the acid (Ka)

For a weak monoprotic acid, we will use the following expression.

Ka = [H⁺]²/Ca

Ka = (1.32 × 10⁻³)²/1.21 = 1.44 × 10⁻⁶

What is the cell potential of an electrochemical cell that has the half-reactions shown below?
Ag⁺ + e⁻ → Ag
Fe → Fe³⁺ + 3e⁻

Answers

Answer:

E°(Ag⁺/Fe°) = 0.836 volt

Explanation:

3Ag⁺ + 3e⁻ => Ag°;            E° = +0.800 volt

Fe° => Fe⁺³ + 3e⁻ ;             E° = -0.036 volt

_________________________________

Fe°(s) + 3Ag⁺(aq) => Fe⁺³(aq) + 3Ag°(s) ...    

E°(Ag⁺/Fe°) = E°(Ag⁺) - E°(Fe°) = 0.800v - ( -0.036v) = 0.836 volt

A Bronsted-Lowry acid is defined as a substance that ________. A Bronsted-Lowry acid is defined as a substance that ________. increases Ka when placed in H2O increases [OH-] when placed in H2O acts as a proton donor acts as a proton acceptor decreases [H ] when placed in H2O

Answers

Answer: A Bronsted-Lowry acid is defined as a substance that acts as a proton donor.

Explanation:

A substance that is able to donate a proton or hydrogen ion to another substance is a Bronsted-Lowry acid.

For example, HCl is a Bronsted-Lowry acid as it dissociates to give a hydrogen ion.

[tex]HCl \rightleftharpoons H^{+} + Cl^{-}[/tex]

Thus, we can conclude that a Bronsted-Lowry acid is defined as a substance that acts as a proton donor.

Aqueous hydrochloric acid will react with solid sodium hydroxide to produce aqueous sodium chloride and liquid water . Suppose 35. g of hydrochloric acid is mixed with 73.0 g of sodium hydroxide. Calculate the minimum mass of hydrochloric acid that could be left over by the chemical reaction. Round your answer to significant digits.

Answers

Answer:

No mass of HCl could be left over by the chemical reaction because is the limting reactant and it is all consumed.

Explanation:

Our reactants are: HCl and NaOH

Products are: NaCl and H₂O

This is a neutralization reaction that can also be called an acid base reaction, an acid and a base react to produce water and a neutral salt, in this case where we have strong acid and base.

Ratio is 1:1. We convert mass to moles:

35 g . 1 mol / 36.45 g = 0.960 moles of HCl

73 g . 1 mol / 40 g = 1.82 moles of NaOH

As ratio is 1:1, for 0.960 moles of HCl we need 0.960 moles of NaOH and for 1.82 moles of NaOH, we need 1.82 moles of acid.

As we only have 0.960 moles of HCl and we need 1.82 moles, no acid remains after the reaction goes complete. HCl is the limiting reactant, so the acid, it is all consumed.

A sample of calcium fluoride was decomposed into the constituent elements. Write a balanced chemical equation for the decomposition reaction. If the sample produced 294 mg of calcium, how many g of fluorine were formed

Answers

Answer:

A sample of calcium fluoride was decomposed into the constituent elements. Write a balanced chemical equation for the decomposition reaction. If the sample produced 294 mg of calcium, how many g of fluorine was formed

Explanation:

The balanced chemical equation for the decomposition of calcium fluoride is shown below:

[tex]CaF_2(s)->Ca(s)+F_2(g)[/tex]

The sample produced 294 g of calcium then, how many grams of fluorine is formed?

From the balanced chemical equation,

1 mol of CaF2 forms 1mol of calcium and 1 mol of fluorine.

That is:

40g of calcium and 38.0 g of fluorine are formed.

then,

If 294 g of calcium is formed then how many grams of fluorine is formed?

[tex]294g Ca * 38g F2 / 40g Ca\\=279.3 g F_2[/tex]

Hence, 279.3 g of fluorine will be formed.

Suppose you perform a titration of an unknown weak acid solution. You start with 4.00 mL of the weak acid and find that it takes 14.2 mL of 0.0500 M NaOH to reach the equivalence point. What is the concentration of the unknown weak acid solution

Answers

Answer:

0.1775 M

Explanation:

The reaction that takes place is:

HA + NaOH → NaA + H₂O

Where HA is the unknown weak acid.

At the equivalence point all HA moles are converted by NaOH. First we calculate how many NaOH moles reacted, using the given concentration and volume:

0.0500 M NaOH * 14.2 mL = 0.71 mmol NaOH

That means that in 4.00 mL of the weak acid solution, there were 0.71 weak acid mmoles. With that in mind we can now calculate the concentration:

0.71 mmol HA / 4.00 mL = 0.1775 M

Pls pls pls help me

Answers

True it is true :) trust

g in the following three compounds(1,2,3) arrange their relative reactivity towards the reagent CH3Cl / AlCl3. Justify your order

Answers

Answer:

3 > 2> 1

Explanation:

Aromatic compounds undergo electrophilic substitution reaction with several electrophiles.

Some substituted benzenes are more reactive towards electrophilic aromatic substitution than unsubstituted benzene.

Certain groups of substituents increase the ease with which an aromatic compound undergoes aromatic substitution.

If we look at the compounds closely, we will notice that only toluene leads to easy reaction with CH3Cl / AlCl3. Thus is due to the +I inductive effect of -CH3 which stabilizes the negatively charged intermediate produced in the reaction.

In the titration of NaOH with vinegar, a student overshot the endpoint (i.e. added too much NaOH solution). How will this affect the calculate percent acetic acid in the vinegar

Answers

Answer:

Overshooting the endpoint leads to a percent acetic acid in vinegar higher than the correct value.

Explanation:

When too much NaOH solution is added, the resulting number of equivalent hydronium (OH⁻) will be higher than what it is in reality. This would directly lead to the number of acetic acid moles in the vinegar being found higher than normal.

In other words, overshooting the endpoint leads to a percent acetic acid in vinegar higher than the correct value.

Predict the products from reaction of 2-hexyne with the following reagents: (a) 2 equiv Br2 (b) 1 equiv HBr (c) Excess HBr (d) Li in NH3 (e) H2O, H2SO4, HgSO4

Answers

Answer:

See explanation and image attached

Explanation:

The reactions of the alkynes involved are shown in the image attached to this answer.

First of all, the reaction of two equivalents of bromine with the alkyne converts it to a saturated compound as shown. One equivalent of HBr converts the alkyne to alkene while excess HBr completely reduces the compound to a saturated compound.

Li/NH3 reduces the alkyne to an alkeneby anti addition to the triple bond.

Reaction of the alkyne with H2O, H2SO4, HgSO4 converts it to an aldehyde as shown.

Which of the following two periods contain the same number of element?
A. 2 & 3
B.3 & 4
c. 4 & 6
D. 2 & 4​

Answers

Answer:

4 and 6

Explanation:

Period 4 has 18 elements and so does period 6.

What is the law of multiple proportions?
A. The proportion of elements to compounds is constant.
B. All elements are found in equal proportions in nature.
C. Different compounds may contain the same elements but may have different ratios of those elements.
D. All compounds contain the same elements in the same proportions.

Answers

Answer:

I think

(d) All compounds contain the same elements in the same properties

Which procedure could a student use to examine an intensive property of a rectangular block of wood
Find the mass.
Record the length. Measure the volume. Determine the density.

Answers

Answer:

density

Explanation:

The procedure that the student could use to examine an intensive property of a rectangular block of wood is to determine its density. Density is intensive because it is the ration between the mass and the volume.

Answer: find the mass option A

Explanation:

Linoleic acid is a polyunsaturated fatty acid found, in ester form, in many fats and oils. Its doubly allylic hydrogens are particularly susceptible to abstraction by radicals, a process that can lead to the oxidative degradation of the fat or oil.

a. True
b. Flase

Answers

Answer:

True.

Explanation:

The information presented in the question above regarding linoleic acid is true. Linoleic acid is, in fact, found in many oils and fats in the ester form. In addition, linoleic acid is considered a polyunsaturated fatty acid, due to the presence of two unsaturations in its composition. Its chemical formula is CH3-(CH2)4-CH=CH-CH2-CH=CH-(CH2)7COOH and it is an essential fatty acid for the human body, as it is essential in the composition of arachidonic acid that is responsible for building muscle, managing body fat thermogenesis, and regulating core protein synthesis.

What should be done if a spectrophotometer reports an absorbance that is too high? Select one: Reposition the cuvette in the spectrophotometer. Pour out half the volume of the sample. Restart the spectrophotometer and try again. Dilute the sample. g

Answers

Answer:

The sample should be diluted

Explanation:

According to Beer Lambert's law, the absorbance of a sample depends on the concentration of the sample.

Hence, if the concentration of the sample is very high, the spectrophotometer will also report a very high value of absorbance.

When this is the case, the sample should simply be diluted and the readings are taken again using the spectrophotometer.

Which equation expresses the solubility product of Zn3(PO4)2?

a. Ksp = [Zn2+][PO43]

b. Ksp = [Zn2+]3 [PO43]2

c. Ksp = 6[Zn2+][PO43]2

d. Ksp = 108[Zn2+][PO43]2​

Answers

AnSweR : -

b. Ksp = [Zn2+]3 [PO43]2

Hope It Helps You ✌️

give one important characteristic of the particles of matter very sort answer​ give

Answers

Answer:

The important characteristics of the particles of matter are – They are very, very small. They have spaces between them. They are constantly moving.

Answer:

They are very very small

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