What is the pH of a 1.0 L buffer made with 0.300 mol of HF (Ka = 6.8 × 10⁻⁴) and 0.200 mol of NaF to which 0.150 mol of HCl were added

Answers

Answer 1

Answer:

pH = 2.21

Explanation:

Hello there!

In this case, according to the reaction between NaF and HCl as the latter is added to the buffer:

[tex]NaF+HCl\rightarrow NaCl+HF[/tex]

It is possible for us to see how more HF is formed as HCl is added and therefore, the capacity of this HF/NaF-buffer is diminished as it turns acid. Therefore, it turns out feasible for us to calculate the consumed moles of NaF and the produced moles of HF due to the change in moles induced by HCl:

[tex]n_{HF}^{new}=0.300mol+0.150mol=0.450mol\\\\n_{NaF}^{new}=0.200mol-0.150mol=0.050mol[/tex]

Next, we calculate the resulting concentrations to further apply the Henderson-Hasselbach equation:

[tex][HF]=\frac{0.450mol}{1.0L} =0.450M[/tex]

[tex][NaF]=\frac{0.050mol}{1.0L} =0.050M[/tex]

Now, calculated the pKa of HF:

[tex]pKa=-log(6.8x10^{-4})=3.17[/tex]

We can proceed to the HH equation:

[tex]pH=pKa+log(\frac{[NaF]}{[HF]} )\\\\pH=3.17+log(\frac{0.05M}{0.45M} )\\\\pH=2.21[/tex]

Best regards!

Answer 2

pH is the measure of the hydrogen or hydronium ion concentration in an aqueous solution. The pH of the buffer made with HF and NaF is 2.21.

What is pH?

pH is the measure of the acidic or the basic content in a solution that can be given by the hydrogen or the hydroxide concentration.

The reaction can be shown as,

[tex]\rm NaF + HCl \rightarrow NaCl + HF[/tex]

New moles of HF is 0.300 + 0.150 = 0.450 moles and new moles of NaF is 0.200 - 0.150 = 0.050 moles.

The concentration is calculated by the Henderson-Hasselbach equation:

[tex]\rm [HF] = \dfrac{0.450 \;\rm mol}{1.0 \;\rm L} = 0.450 \;\rm M[/tex]

And,

[tex]\rm [NaF] = \dfrac{0.050\;\rm mol}{1.0 \;\rm L} = 0.050\;\rm M[/tex]

pKa of hydrogen fluoride is calculated as:

[tex]\rm pKa = - log (6.8 \times 10^{-4}) = 3.17[/tex]

The pH from the pKa can be calculated as:

[tex]\begin{aligned}\rm pH &=\rm pKa + log (\dfrac{[NaF]}{[HF]})\\\\&= 3.17 + \rm log (\dfrac{0.05}{0.45})\\\\&= 2.21\end{aligned}[/tex]

Therefore, the pH is 2.21.

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Related Questions

HELP a #QUEEN out pls??


Type the correct answer in each box.

Balance the equation.


_____SiO2 + ______CaC2 → _____Si + _______CaO + _____CO2

Answers

The coefficients, in order of the blanks, are 5, 2, 5, 2, 4.

Pt4 science......

Select correct answer ♡ !

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A is correct!

2 electrons in the outer shell!

Mark with crown please!

10 How does no-till farming help the environment?
A It decreases soil erosion.
C It increases fertilizer use.
B It increases soil removal.
D It decreases crop yield.

Answers

Answer: Answer is A it will decrease soil erosion

Explanation:it just will trust me

Answer:

A.

Explanation:

the soil will not loosen when u till it

a ceiling fan's blades collect dust faster than other objects in a room. the constant pushing and rubbing against the air provide a cool breeze for the people in the room. what causes the ceiling fan´s blade to collect dust so quickly.

Answers

As the blades rotate, they experience frictional forces as they `rub' against the air; this knocks electrons around, causing the blades to build up a net charge. The charged dust particles then stick to the charged areas of the blades. "The leading edge of the blades usually develops the thickest layer of dust.

To solve this we must be knowing each and every concept related to dust. Therefore,  frictional forces allow the ceiling fan´s blade to collect dust so quickly.

What is dust?

Dust stirred up by automobiles on the road may account for 33% overall air pollution. Deposits of vehicle or commercial exhaust gas, particles through tire and braking wear, dust from paved streets or potholes, plus dust from building sites all contribute to road dust.

As the blades revolve, frictional forces cause them to 'rub' against the air, knocking electrons around and allowing the blades to accumulate a net charge. The electrified dust particles are subsequently attracted to the charged portions of the blades. Typically, the sharp end of the blades creates the heaviest coating of dust.

Therefore,  frictional forces allow the ceiling fan´s blade to collect dust so quickly.

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1. The production of a slightly soluble solid compound in a double-
displacement reaction results in the formation of a
a. gas.
b. precipitate.
C. combustion reaction.
d. halogen.

Answers

Answer: precipitate

Explanation:

describe what happens when atoms release light?​

Answers

Answer:

hi

Explanation:

Light is the result of electrons moving between defined energy levels in an atom, called shells.

Materials that allow electrons to move easily from atom to atom are called _____________.

Answers

Answer:

Explanation:

conductors

Conductors
Your welcome

PLEASE HELP
The theory of plate tectonics is supported by evidence that crustal plates move relative to each other. How does this observation support the theory of plate tectonics?
It suggests that plates are dragged around by ocean currents.
It suggests that plates are dragged around by air currents.
It suggests that plates can move independently of one another.
It suggests that plates cannot move independently of one another.

Answers

Answer:

non independantly

Explanation:

During a tug-of-war, the rope accelerates towards the left. What is true about the forces acting on the rope?

Answers

Explanation:

Forces are given many names, such as push, pull, thrust, lift, weight, friction, and tension. Traditionally, forces have been grouped into several categories and given names relating to their source, how they are transmitted, or their effects. The most important of these categories are discussed in this section, together with some interesting applications. Further examples of forces are discussed later in this text.

1.The symbol of an atom changes when the number of _______
changes.
2.The net charge of an atom depends on ___________ and
_________.
3.The atom is neutral when ________ and _________ are equal.
4.The mass number of an atom depends on __________ and
_________.

Answers

Answer:

1. proton

2. electrons and protons

3. protons and electrons

4. protons and neutrons

Explanation:

Determine the ions of ammonium, in 870.4x10-23 grams of (NH4)3PO4. Round the results to the tenths.

Answers

Answer: if your trying to say what 4x10-23 is the answer is 17

and if ur also trying to say whats 870.4x10-23 the answer is 8681 have a nice day!

Explanation:

also and what is (NH4)3PO4 if its a file code or link your not allowed to post that

Explain what helps convert non-rich oxygen blood cells back to oxygen rich cells?

Answers

Answer:

As blood travels through the body, oxygen is used up, and the blood becomes oxygen poor. Oxygen-poor blood returns from the body to the heart through the superior vena cava (SVC) and inferior vena cava (IVC), the two main veins that bring blood back to the heart.

Explanation:

Select the correct answer.

Which statement best describes how chemical equations demonstrate conservation of mass?

A.
The number of reactants is the same as the number of products.
B.
The compounds are the same on each side of the reaction.
C.
The number of atoms of each element is the same on each side of the equation.
D.
The state of matter is the same on each side of the equation.

Answers

"C" is correct.

The Law of Conservation of Mass states that matter can be neither created nor destroyed. This is evident in chemical equations as you will always start and end with the same amount of atoms of every element. They are all still there; they have just been rearranged.

Answer: C) The number of atoms of each element is the same on each side of the equation.

Explanation: Mass cannot be created nor destroyed.

The half life of potassium 40 is approximately 1.25 billion years. An igneous rock is found to contain about 1/4 of its original mass of potassium 40. The approximate age of the rock is _____ billion years.

Answers

Answer:

2.5 billion years

Explanation:

A student prepares four different aqueous NaCl solutions according to the table. Which solution will have the highest molarity?

Answers

Answer:

what did you end up guessing

Explanation:

What are the mole ratios of the following chemical equation: C3H8 + 5O2 --> 3CO2 + 4H2O?

Answers

Answer:Redox and combustion.

Explanation:

C3H8) reacts with oxygen in the air, so  C3H8(g) + 5O2(g) = 3CO2(g) + 4H2O(g) Classification: Redox and combustion.

What number represents a mole?
5
1
4
14
8
6
19

Answers

6 is Avogadro’s number for one mole

Sodium chlorate is used to produce yellow fireworks. Heating sodium chlorate creates oxygen and sodium chloride. How many moles of sodium chlorate is needed to produce 5.70 moles of oxygen?

Answers

https://www.geneva304.org/Downloads/ch%209%20key6.pd

this is what i found add an "f" at the end and search

what is geography in science​

Answers

The study of earth. Geo means earth

Can someone help me ❤️❤️❤️

Answers

Answer:

i think the answer would be C

Explanation:

no matter what you do to the jar the mass will stay the same. unless you add more nails

What is the job or function of cell walls in plant cellls

Answers

Answer:

The cell wall surrounds the plasma membrane of plant cells and provides tensile strength and protection against mechanical and osmotic stress. It also allows cells to develop turgor pressure, which is the pressure of the cell contents against the cell wall.

Explanation:

ion

The cell walls in plant cells provide tensile strength and protection against mechanical and osmotic stress. It also allows cells to develop turgor pressure, which is the pressure of the cell contents against the cell wall.
Source:Nature.com

Can you identify what object is being represented by the model on the right?

basketball

cell

Earth


The answer is. B. Cell

Answers

Earth...............

Answer:

Cell lol

Explanation:

answer B

A chemical equation representing the reaction of water (HOH) and hydrochloride acid (HCI) is shown.
HOH + HCl + Cl + H2O
Which of the following statements best explains the chemical action of the reactants in the equation?

Answers

Answer:

That is Hydrolysis reaction.

[tex]HCl _{(aq)} \: + \: _{(aq)} \: - - > \: H ^{ + }_{(aq)} \: + \: Cl {}^{ - } _{(aq)}[/tex]

Compare a low-dose rate internal radiation treatment to a high dose rate internal treatment. What do you think are the positives and negatives of each?

Answers

Internal radiation is also called brachytherapy. A radioactive implant is put inside the body in or near the tumor. Getting the implant placed is usually a painless procedure. Depending on your type of cancer and treatment plan, you might get a temporary or a permanent implant. Internal radiation therapy (brachytherapy) allows a higher dose of radiation in a smaller area than might be possible with external radiation treatment. It uses a radiation source that’s usually sealed in a small holder called an implant. Different types of implants may be called pellets, seeds, ribbons, wires, needles, capsules, balloons, or tubes. No matter which type of implant is used, it is placed in your body, very close to or inside the tumor. This way the radiation harms as few normal cells as possible.

During intracavitary radiation, the radioactive source is placed in a body cavity (space) , such as the rectum or uterus.
With interstitial radiation, the implants are placed in or near the tumor, but not in a body cavity. The implant procedure is usually done in a hospital operating room designed to keep the radiation inside the room. You’ll get anesthesia, which may be either general (where drugs are used to put you into a deep sleep so that you don’t feel pain) or local (where part of your body is numbed).

One or more implants is put into the body cavity or tissue with an applicator, usually a metal tube or a plastic tube called a catheter. Imaging tests (an x-ray, ultrasound, MRI, or CT scan) are usually used during the procedure to find the exact place the implant needs to go.

Before being placed, implants are kept in containers that hold the radiation inside so it can’t affect others. The health professionals handling the implants may wear special gear that protects them from exposure once the implants are taken out of the container. High-dose-rate (HDR) brachytherapy allows a person to be treated for several minutes at a time with a powerful radioactive source that’s put in the applicator. The source is removed after 10 to 20 minutes. This may be repeated twice a day over a few days, or once a day over the course of a few weeks. The radioactive material is not left in your body. The applicator might be left in place between treatments, or it might be put in before each treatment.

People getting HDR sometimes stay in the hospital if it involves multiple day treatments and if the applicator is left in place. There may be special precautions to take after the treatment, so be sure to talk to the cancer care team about this. In this approach, the implant gives off lower doses of radiation over a longer period.

Some implants are left in from 1 to a few days and then removed. You’ll probably have to stay in the hospital, sometimes in a special room, during treatment. For larger implants, you might have to stay in bed and lie still to keep it from moving.

Some smaller implants (such as the seeds or pellets) are left in place and never taken out. Over the course of several weeks they stop giving off radiation. The seeds or pellets are about the size of rice grains and rarely cause problems. If your implants are to be left in, you may be able to go home the same day they’re put in. There may be special precautions to take, so be sure to talk to the cancer care team about this.




How can the strength of an acid be determined using titration? (100 POINTS!)

Answers

Answer:

Explanation:

A titration in general is used to determine the concentration of something with a solution of known solution. For acid, a base solution of known concentration is added slowly. The end-point is determined by using a pH indicator. When the acid is neutralized at the end, note the amount of base solution used and the strength of acid can be calculated.

Note that the quantity of base solution utilised and the acid strength can be estimated after the acid has been neutralised.

What is titration?

Titration is a method of chemical analysis where the quantity of a sample's constituents is established by adding a precisely measured amount of something else with which the component that is wanted will react in a specific, known proportion.

A burette, which is essentially a long, graded measurement tube with a stopper and a tube for injection at its bottom end, is used to gradually administer a standard solution of titrating reagent, and titrant, to a specified concentration. When the point of equal value is achieved, the addition is terminated. Note that the quantity of base solution utilised and the acid strength can be estimated after the acid has been neutralised.

Therefore, note that the quantity of base solution utilised and the acid strength can be estimated after the acid has been neutralised.

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If 34.2 g of NaOH are dissolved in water to make a 750 mL solution, what is the molarity of the solution?

Answers

Answer:

1.14 M

Explanation:

First divide the mass of NaOH by the molar mass of NaOH. Then divide by the volume to get molarity.

34.2 g / 39.997 g/mol = 0.855 mol NaOH

0.855 mol NaOH / 0.750 L = 1.14 M NaOH

Write two paragraphs about what would happen if your whole body was put in a low pressure environment ?

Answers

Answer:

Reduced air pressure also has a serious effect on the human body. Reduced air pressure means that there is less oxygen available to the body. For lungs to inflate, the air pressure in your lungs has to be less than the air outside the lungs. This is because air moves from high-pressure areas to low-pressure areas.

Explanation:

Reduced air pressure also has a serious effect on the human body. Reduced air pressure means that there is less oxygen available to the body. For lungs to inflate, the air pressure in your lungs has to be less than the air outside the lungs. This is because air moves from high-pressure areas to low-pressure areas.

Which best describes the relationship between the terms frequency, wavelength, and hertz?

Answers

Answer:

The correct answer is - Frequency is the number of wavelengths, which is measured in hertz.

Explanation:

Frequency is the number of waves that go through a fixed point at a particular time. Hertz is the SI unit for frequency which means that one hertz is equal to a unit number of waver passes in a unit time to a fixed point.

As the frequency of a wave increases which means the number of waves increases in the unit time, the shorter the wavelength will be.

a higher frequency wave has more energy than a lower frequency wave with the same amplitude.

How many milliliters of 4.00 M NaOH are required to exactly neutralize 50.0 milliliters of a 2.00 M solution of HNO3 ?

Answers

Answer: The volume of [tex]NaOH[/tex] required is 25.0 ml

Explanation:

According to the neutralization law,

[tex]n_1M_1V_1=n_2M_2V_2[/tex]

where,

[tex]n_1[/tex] = basicity [tex]HNO_3[/tex] = 1

[tex]M_1[/tex] = molarity of [tex]HNO_3[/tex] solution = 2.00 M

[tex]V_1[/tex] = volume of  [tex]HNO_3[/tex] solution = 50.0 ml

[tex]n_2[/tex] = acidity of [tex]NaOH[/tex] = 1

[tex]M_1[/tex] = molarity of [tex]NaOH[/tex] solution = 4.00 M

[tex]V_1[/tex] = volume of  [tex]NaOH[/tex] solution =  ?

Putting in the values we get:

[tex]1\times 2.00\times 50.0=1\times 4.00\times V_2[/tex]

[tex]V_2=25.0ml[/tex]

Therefore, volume of [tex]NaOH[/tex] required is 25.0 ml

The volume of 4.00 M NaOH is required to exactly neutralize 50.0 ml of a solution of a 2.00 M solution of [tex]HNO_3[/tex] is 25.0 ml.

What is [tex]HNO_3[/tex]?

[tex]HNO_3[/tex] is nitric acid also known as the spirit of niter. It is colorless in its original form but appears yellow-colored.

By the neutralization law

[tex]n_1M_1V_1 = n_2M_2V_2[/tex]

n1 = 1

M1 = 2.00

M2 = 4.00

V1 = 50.0 ml

n2 = NaOH = 1

Putting the value in the formula

[tex]1 \times 2.00 \times 5.00 ml = 1 \times 4.00 \times V_2\\\\V_2 = 25.0\; ml[/tex]

Thus, the volume of NaOH required is 25.0 ml.

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65 g of NaOH is dissolved to make 500 mL of solution. Find moles of NaPH and Molarity of solution.

Answers

Answer:

3.25 M

Explanation:

Number of moles = mass/ molar mass

mass of  NaOH = 65 g

Molar mass of NaOH = 40 g/mol

Number of moles of NaOH = 65g/40 g/mol = 1.625 moles

Let us recall that;

n = CV

n = number of moles of solute

C = concentration of solution

V = volume of solution

C = n/V

n = 1.625 moles

V = 500/1000 L = 0.5 L

C = 1.625 moles/0.5

C = 3.25 M

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