To prepare 800mL of 1M phosphate buffer of pH 7.2 (PKa=7.1), by using salt = K2HPO4 and acid = KH2PO4, the quantity of salt required is

Answers

Answer 1

Answer:

78.04g of 0.448 moles must be added

Explanation:

Using H-H equation we can find the pH of the buffer:

pH = pKa + log [A⁻] / [HA]

Where pH is the pH of the buffer = 7.2

pKa = 7.1

[A⁻] = [K₂HPO₄]

[HA] = [KH₂PO₄]

Replacing:

7.2 = 7.1 + log [K₂HPO₄] / [KH₂PO₄]

0.1 = log [K₂HPO₄] / [KH₂PO₄]

1.2589 = [K₂HPO₄] / [KH₂PO₄] (1)

And as the  concentration of the buffer is:

1M = [K₂HPO₄] + [KH₂PO₄] (2)

Replacing (2) in (1):

1.2589 = 1M - [KH₂PO₄] / [KH₂PO₄]

1.2589 [KH₂PO₄] = 1M - [KH₂PO₄]

2.2589 [KH₂PO₄] = 1M

[KH₂PO₄] = 0.44M

And [K₂HPO₄] = 0.56M

In 800mL = 0.8L:

0.8L * (0.56mol / L) = 0.448 moles K₂HPO₄. The mass is -Molar mass K₂HPO₄: 174.2g/mol-:

0.448 moles * (174.2g / mol) =

78.04g of 0.448 moles must be added

Related Questions

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How are the cells produced through mitosis and meiosis different?

A.
They have different cell shapes.

B.
They have different numbers of chromosomes.

C.
They have different levels of activity in the ribosomes.

D.
They have different components in the cell membrane.

Answers

Answer:

c.

They have different levels of activity in the ribosomes.

Answer: B. Mitosis produces two genetically identical daughter cells but meiosis produces four genetically different daughter cells.

Explanation:

Mitosis is the equational division in which two identical daughter cells are formed.Mitosis does not involve crossing over of the homologous chromosomes.It occurs in four steps which are:ProphaseMetaphaseAnaphaseTelophaseMeiosis is reductional division in which four different daughter cells are formed.It proceed through two cycles i.e meiosis I and meiosis IIMeiosis I contains:Prophase I which contains:I HOPE THIS IS HELPFUL HAVE A AWESOME NIGHT/DAY❤️✨

What is the compound name for Bel?

Answers

The answer should be Aegle marmelos

Please help me i really need help

Answers

Answer:

H2o i think

Explanation:

2.107 × 10^24 calculate the number of moles​

Answers

2.1070000000000003e+24

In which scenario is the object in equilibrium?
A
the rope being pulled
B
the book on the table
С
the weight being lifted
D
the car gaining speed

Answers

Answer:

d i believe

Explanation:

Answer:

It's 100% B, The book on the table.

Explanation:

How does a flux capacitor deteriorate under high octane pressure?

Answers

The high octane pressure interferes with the neutrino conjugations, which in turn decrease the fusion potential to below optimal levels. If this is allowed to continue, the the sub-optimal fusion potential will degrade the bucking electrodes and final flux concentration vortex. At that point the flux capacitor will deteriorate quickly and will likely not be repairable.

What is the freezing point of solution that has 185.25 grams of Ca(OH)2 (formula mass = 74.1) dissolved in 2,500 grams of water at standard pressure?

Answers

Answer:

The freezing point depression ∆T = KF·m where KF is the molal freezing point depression constant and m is the molality of the solute. Rearrangement gives: mol solute = (m) x (kg solvent) where kg of solvent is the mass of the solvent (lauric acid) in the mixture. This gives the moles of the solute.

Explanation:

Does this help at all??

What is one energy transformation that is taking place in the photo?

radiant energy to thermal energy

thermal energy to nuclear energy

chemical energy to thermal energy

radiant energy to chemical energy

Answers

Answer:

Radiant energy to chemical energy

Explanation:

Got it right on edge 2021

One energy transformation that is taking place in the photosynthesis process is radiant energy to chemical energy.

What is energy transformation?

Energy transformation is the process in which one form of energy converted into another form of energy.

What is photosynthesis process?

Photosynthesis process is defined as the process in which plants makes their own food by using the carbon dioxide, water and sunlight in the chlorophyll.

The balanced chemical equation of photosynthesis process is

6CO2 + 6H2O → C6H12O6 + 6O2.

Since, it have 6 atoms of carbon, 12 atoms of hydrogen and 18 atoms of oxygen on both side. So, it is balanced.

Since, sunlight which it take is in the form of radiant and convert it into chemical energy.

Thus, we concluded that the energy transformation that is taking place in the photosynthesis process is radiant energy to chemical energy.

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How many grams of Sn will be created when 114 grams of SnO2 react with excess H2? SnO2 + H2 ->Sn + H2O
I

Answers

Explanation:

CNN vfbtgnynynynynyuybunujy

What is the distance from Point A to point B

help!!

Answers

Answer:

60

Explanation:

there's 5 lines, and 800-700=100 each line represents 20 because 20×5=100.

from a to b, there's 3 lines and 3×20=60

While both comets and asteroids are found to orbit the Sun in our Solar System, which choice correctly explains how they are different?

Comets are much larger than asteroids.


Asteroids form a tail, and comets do not.


Asteroids have long orbits around the Sun. Comets orbit between Mars and Jupiter.


Comets are made of ice, dust, and rocky material. Asteroids are made of rock and metal material.

Answers

Answer:Comets are made of ice,dust,and rocky material.Asteroids are made of rock and metal material

Answer:

D

i think

Explanation:

Necesito las caracteristicas fisicas y quimicas de la teoria inorganica del petroleo

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Answer:

de lapora en ciesta coma bodre sin una jacsinis loadera comastora jingla belaa

Explanation:

Most representative metal atoms tend to gain enough electrons to attain a stable noble gas (octet) configuration.

True or False

Answers

Answer:

False

Explanation:

Non- metals tend to gain electrons easily, metals tend to lose electrons easily

For example, oxygen, a non-gas, when it is an ion, has the option to lose 6 electrons to become like helium, or gain 2 electrons to become like the noble gas neon. However, it becomes like neon for 2 reasons.

A. As a general rule, atoms lose/gain the LEAST amount of electrons.

B. Oxygen is a nonmetal, therefore, to become like a Noble Gas, it would gain, as non-metals usually would, 2 electrons.

How many moles of nitrogen are in 1 mole of Al(NO3)3?
O A. 4 moles of nitrogen
O B. 1 mole of nitrogen
C. 3 moles of nitrogen
O D. 7 moles of nitrogen

Answers

Answer:

c i think

Explanation:

How many protons and neutrons are in an atom of B-13?

Answers

Answer:

6 protons and neutrons

Explanation:

How many particles are present in a 56.9 mole sample of calcium hydroxide?

Answers

Answer:

Particles?  Calcium hydroxide does not exist as discrete molecules, but as a network solid.  The only way you would have separate particles, is if the calcium hydroxide was dissolved in a boatload of water.  Ca(OH)2 is not all that soluble in water.  Nonetheless, assume a lot of water, enough to dissolve 56.9 moles.

Ca(OH)2 --> Ca2+ + 2OH-

56.9 moles Ca(OH)3 x (3 moles ions / 1 mol Ca(OH)2) = 170.7 mol ions

==================

Percent composition of CuNO3......molar mass = 125.5 g/mol

Cu.... 1 x 63.5 / 125.5 x 100 = 50.6% Cu

N ......1 x 14.0 / 125.5 x 100 = 11.2% N

O .....3 x 16.0 / 125.5 x 100 = 38.2% O

(hope this helps can i plz have brainlist :D hehe)

Explanation:

The ion which forms from element 36 is known as
A. Krypton ion
B. Kryptonite
C. kryptonide ion
D. this ion does not exist

Answers

Answer: A
Krypton is a chemical element with the symbol Kr and atomic number 36.

Name four elements that are similar to Iodine.

Answers

Answer:

Chlorine, astatine, bromine, and fluorine.

Answer:

Fluorine, Chlorine, Bromine, and Astatine

Explanation:

they are all in group 17 meaning they have similer chemical properties.

Which of the elements shown has an atomic mass of 20 amu?

A) A
B) B
C) C
D) D

Answers

The elements shown have an atomic mass of 20 amu is Neon.

What is atomic mass?

The atomic number of an atom is its total number of protons and neutrons.

Neon has an atomic mass of about 20 this isotope contains 10 protons and 10 neutrons.

Actually, Neon would be listed as having an atomic mass of about 20.18 because of a mixture of isotopes.

Z= Atomic number the number of protons in the nucleus which defines the element.

In this case,  Z=10 and this means neon but there are also 10 neurons in the nucleus of the major isotope which gives it 20Ne.

Hence, option D is the correct answer.

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Which element is a noble gas? pls help!!

Answers

Answer:

HE (helium)

Explanation:

Answer: Helium

Explanation: If you look at a periodic table noble gasses are on the far right side

What is Geothermal energy? How does it work? (2-3 sentences is good enough) thx :3

WILL MARK BRAINLIEST WHOEVER ANSWERS THIS FIRST:DDD!!!

Answers

Answer:

Geothermal power plants, which use heat from deep inside the Earth to generate steam to make electricity. Geothermal heat pumps, which tap into heat close to the Earth's surface to heat water or provide heat for buildings

Explanation:

The period of time needed for a radioisotope to lose one-half of its activity is known as that isotopes

Answers

Explanation:

The radioactive scattering technique is called radioactive degradation. For each radioactive isotope, the natural radioactive cycle is special and is determined by a period of time termed a half-life. One half-life was its time needed to experience radioactivity for half of both the radioactive nuclei.

The three properties of objects are:

Answers

Answer:

they have shape.

they have volume.

they occupy space.

What happens to the decaying proton during positron emission?

Answers

Answer:

Turns into a neutron and a gamma ray and a positron are released.

Explanation:

What is the molarity of a solution if 0.529 moles of LiCl is dissolved in 687 mL of water?

Answers

Answer:

Molarity of solution = 0.77 (Approx.)

Explanation:

Given:

Moles of LiCl = 0.529

Volume of water  = 687

Find:

Molarity of solution

Computation:

Molarity of solution = [Moles/Volume]1000

Molarity of solution = [0.529/687]1000

Molarity of solution = 0.77 (Approx.)

An electron in an atom of hydrogen goes from energy level 6 to energy level 2. What is the wavelength of the electromagnetic radiation emitted?

Answers

Answer:

410 nm

Explanation:

when an electron falls from ni=6 to nf=2 , a photon of wavelength 410 nm is emitted.

When an electron falls then the wavelength of the electromagnetic radiation emitted is = 410 nm.

What is electromagnetic wavelength?

When The Electromagnetic wavelength directs to the measured distance between the trough or crest of each adjacent wave generated by the electromagnetic disturbance.

When the wavelength of electromagnetic radiation is comparable to the de Broglie wavelength of its quantum (photon).

Now we are Showing that the wavelength of electromagnetic radiation is comparable to the de Broglie wavelength of its quantum (photon).

Therefore, when an electron falls from ni=6 to nf=2, a photon of wavelength 410 nm is emitted.

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ik, i’m stup!d. please help:(

Answers

Answer:

a

Explanation:

Chemical bonds form because: a. The atoms have more energy bonded together than separated b. The atoms have less energy bonded together than separated

Answers

Answer:

A. The atoms have more energy together than separated.

Explanation:

There are several reasons why a chemical bond could take place. Adding things like heat or pressure stimulate the atoms to force a reaction to take place. But when it comes down to it, the intramolecular forces of the electrons  pull each other to form chemical bonds (represented by Valence electrons). The stronger these are, the more likely they are going to bond.

Atoms with lower forces typically don't typically bond with other atoms of lower forces.

how do i word a formal letter to a teacher saying i didn't pay attention during the science lessons and i now have no idea what to do? by the way, this is on edge so i haven't been on a call, or met my teacher in person.

Answers

Explanation:

Hello mr/mrs (name) I unfortunately couldn't pay attention to the class due to some issues I had therefore I don't know what we are doing in class

OR

Hello mr/mrs (name) I could understand what we were doing in class I would like it if you could break it down more or explain better to me

OR just say something it had something to do with your internet such as

Hello mr/mrs (name) I didn't understand what you were saying during our class due to some of my internet issues I was have throughout the day. I hope you can explain what we did during the class.

Those may be some of my excuses I've used before

they have worked for me:)

I don't know if that helped?:/

how do we make our natural resources last for generations to come?

Answers

Answer:

We can use non-plastic water bottles, use reusable ziploc bags, use a felt grocery bag, fill a bucket of water while you are showering then afterwards use it to water plants.

this all can help because it is our reusable and the plastic things can end up in the ocean (ocean/ water is a natural resource).

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