1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
arsen [322]
3 years ago
13

Consider a solution prepared by mixing the following:50.0 mL of 0.100 M Na3PO4100.0 mL of 0.0500 M KOH200.0 mL of 0.0750 M HCl50

.0 mL of 0.150 M NaCNDetermine the volume of 0.100 M HNO3 that must be added to this mixture to achieve a nal pH value of 7.21.
Chemistry
1 answer:
Juliette [100K]3 years ago
5 0

Answer:

you must add 50 mL

Explanation:

Hi

KOH is a strong base and by adding 100mL 0.05M you will have an amount of 5 millimol.

NaCN is a base and by adding 50 mL 0,150 M you will have an amount of 7,5 mmol.

HCl is a acid and by adding 200 mL 0,075 M you will have an amount of 15 mmol.

The acid reacts with the bases leaving 2.5 mmol unreacted.

Na3PO4 is a base and by adding 50 mL 0,1 M you will have an amount of 5 mmol.

The 2.5 mmol of acid react with the base PO4 ^ -3 forming a regulatory solution of PO4 ^ -3 and HPO4 ^ -2 of pKa 2.12

5 mmol of acid (HNO3) must be added to obtain a regulatory solution formed by the same amount of HPO4 ^ -2 (2.5 mmol) and H2PO4 ^ -1 (2.5 mmol) with pKa 7.21

Considering a quantity of 5 mmol of HNO3 of concentration 0.1 M, 50 mL must be added.

To calculate the pH of the regulatory solution you should consider pH = pKa × Ca / Cb pH = 7.21 × 2.5 / 2.5 = 7.21 Being in the same solution the volume is the same and can be simplified to achieve a faster calculation.

successes with your homework

You might be interested in
How much energy must be supplied to break a single 21Ne nucleus into separated protons and neutrons if the nucleus has a mass of
love history [14]

Answer:

1)There is 2.68 * 10^-11 J of energy needed

2) The nuclear binding energy for 1 mol of Ne is 1.6 *10^13 J/mol

Explanation:

Step 1: Data given

The nucleus of a21Ne atom has a amass of 20.98846 amu.

Step 2: Calculate number of protons and neutrons

The number of electrons and protons in an 21Ne atom = 10

The number of neutrons = 21 -10 =11

Step 3: mass of the atom

Mass of a proton = 1.00727647 u

Mass of a neutron = 1.0086649 u

The mass of the atom = mass of all neutrons + mass of protons

Mass of atom = 11*1.0086649 + 10*1.00727647  = 21.1680786 amu

Step 4: Calculate change of mass

The change in mass = Mass of atom - mass of neon

Δmass = 21.1680786 - 20.98846

Δmass = 0.1796186

Step 5: Calculate mass for a single nucleus

The change of mass for a single nucleus is = Δmass / number of avogadro

Δmass of nucleus = 0.1796186 / 6.022*10^23

Δmass of nucleus =2.98 * 10^-25 grams = 2.98 * 10^-28 kg

Step 6: Calculate energy to break a Ne nucleus

Calculate the amount of energy to break a Ne nucleus

ΔEnucleus = Δmass of nucleus * c²

⇒ with c = 2.9979 *10^8 m/s

ΔEnucleus = 2.98 * 10^-28 kg * (2.9979*10^8)² = 2.68 * 10^-11 J

What is the nuclear binding energy for 1 mol of Ne?

ΔE= ΔEnucleus * number of avogadro

ΔE= 2.68 * 10^-11 J * 6.022*10^23

ΔE= 1.6 *10^13 J/mol

3 0
3 years ago
Which plate, oceanic or continental, must be more dense?
musickatia [10]

Answer:

Oceanic & Continental Plates

The oceanic plate is denser and sinks due to its lower buoyancy. It's sucked into the asthenosphere and is melted deeper into the Earth, called a subduction zone. The continental plate is less dense and floats over the top of it since it is more buoyant

4 0
3 years ago
5. Students hypothesize that temperature is a limiting factor for the germination of seeds. They carry out an experiment to
Lelechka [254]

Answer:

keep adding to on each term its quit simple

8 0
2 years ago
Calculate the mass of beryllium (Be) needed to completely react with 18.9 g nitrogen gas (N2) to produce Bez N2, which is the on
choli [55]

Answer:

C = 18.29 g  

Explanation:

Given data:

Mass of beryllium needed = ?

Mass of nitrogen = 18.9 g

Solution:

Chemical equation:

3Be + N₂    →    Be₃N₂

now we will calculate the number of moles of nitrogen:

Number of moles = mass/molar mass

Number of moles = 18.9 g/ 28 g/mol

Number of moles = 0.675 mol

Now we will compare the moles of nitrogen and Be from balance chemical equation.

                     N₂        :       Be        

                       1          :       3

                  0.675       :      3/1×0.675 = 2.03 mol

Number of moles of Be needed are 2.03 mol.

Mass of Beryllium:

Mass = number of moles × molar mass

Mass = 2.03 mol ×   9.01 g/mol

Mass = 18.29 g  

4 0
3 years ago
Which of the following would be produced when two or more different atoms bond chemically?
ExtremeBDS [4]

Answer:

When two or more atoms chemically bond with each other, the resultant chemical structure is a molecule. The familiar water molecule, H2O, consists of two hydrogen atoms and one oxygen atom; these bond together to form water,  irdk but it's either C or D

Explanation:

hope this helps have a good rest of your day :) ❤

7 0
3 years ago
Other questions:
  • Why did the United States government set aside land for the first national parks?
    7·1 answer
  • The difference between isotopes for the same element will be found in the atoms'
    15·1 answer
  • What is the mass of 0.50 moles of Na? 11 grams 46 grams 3.0 × 1023 grams 6.0 × 1023 grams
    11·2 answers
  • Which of the following represents the mass of an oxygen molecule?
    8·1 answer
  • How may moles are in 145.54 g of SIO2
    14·1 answer
  • How did Democritus help our understanding of the atom?
    13·1 answer
  • What is the balanced chemical equation for the reaction used to calculate ΔH∘f of SrCO3(s)?
    15·1 answer
  • What is the molarity of a naoh solution if 28.2 ml of a 0.355 m h2so4 solution is required to neutralize a 25.0-ml sample of the
    10·2 answers
  • Which atom in each pair that has the largest atomic radius.
    14·1 answer
  • Easy points if you actually try :)<br> How's your day going today?<br><br> Stay great! &lt;3
    14·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!