As part of a soil analysis on a plot of land, a scientist wants to determine the ammonium content using gravimetric analysis with sodium tetraphenylborate, Na+B(C6H5)−4. Unfortunately, the amount of potassium, which also precipitates with sodium tetraphenylborate, is non‑negligible and must be accounted for in the analysis. Assume that all potassium in the soil is present as K2CO3 and all ammonium is present as NH4Cl.
A 5.025 g soil sample was dissolved to give 0.500 L of solution. A 100.0 mL aliquot was acidified and excess sodium tetraphenylborate was added to precipitate both K+ K + and NH+4 ions completely.
Compound Formula mass
B(C6H5)−4+K+⟶KB(C6H5)4(s) KB(C6H5)4 358.33 g/mol
B(C6H5)−4+NH+4⟶NH4B(C6H5)4(s) NH4B(C6H5)4 337.27 g/mol
K2CO3 138.21 g/mol
NH4Cl 53.492 g/mol
The resulting precipitate amounted to 0.277 g. A new 200.0 mL aliquot of the original solution was made alkaline and heated to remove all of the NH+4 as NH3. The resulting solution was then acidified, and excess sodium tetraphenylborate was added to give 0.105 g of precipitate.
Find the mass percentages of NH4Cl and K2CO3 in the original solid.
______ %NH4CL
______ %K2CO3

Answers

Answer 1

Answer:

Mass percentage of NH₄Cl = 3.54%

Mass percentage of K₂CO₃ = 1.01%

Explanation:

If a 200.0 mL aliquot produced  0.105 g of KB(C₆H₅)₄, then a 100.0 mL aliquot would produce 1/2 * 0.105 g = 0.0525 g of KB(C₆H₅)₄.

Therefore, mass of NH₄B(C₆H₅)₄ in the 100.0 ml aliquot = (0.277 - 0.0525)g = 0.2245 g

Number of moles of NH₄B(C₆H₅)₄ in 0.2245 g = 0.2245 g/ 337.27 g/mol = 0.0006656 moles

In 500 ml solution, number of moles present = 0.0006656 * 500/100 = 0.003328 moles.

From equation of the reaction; mole ratio of  NH₄⁺ and NH₄B(C₆H₅)₄ = 1:1

Similarly, mole ratio of  NH₄⁺ and NH₄Cl = 1:1

Therefore, moles of NH₄Cl in 500 ml sample = 0.003328 moles

Mass of NH₄Cl  = 0.003328 mol * 53.492 g/mol = 0.178 g

Mass percentage of NH₄Cl = (0.178/5.025) * 100% = 3.54%

Number of moles of KB(C₆H₅)₄ in 0.105 g (precipitated from 200.0 ml aliquot) = 0.105 g/ 358.33 g/mol = 0.000293 moles

In 500 ml solution, number of moles present = 0.000293 * 500/200 = 0.0007326 moles.

From equation of the reaction; mole ratio of  K⁺ and KB(C₆H₅)₄ = 1:1

Similarly, mole ratio of  K⁺ and K₂CO₃ = 2:1

Therefore, moles of K₂CO₃ in 500 ml sample = 0.0007326/2 moles =  0.0003663 moles

Mass of  K₂CO₃ = 0.0003663 mol * 138.21 g/mol = 0.05063 g

Mass percentage of K₂CO₃ = (0.05063/5.025) * 100% = 1.01%


Related Questions

5. Explain why the particle diagram below represents a chemical change.
plsss help!!!

Answers

Answer:

the atoms are rearranged

Explanation:

they are just in a diff order

The particle diagram represents a chemical change because the breaking of old chemical bonds and the formation of new chemical bonds occurs and a completely new substance is formed.

What is the chemical change?

A chemical change is when a chemical substance is completely transformed into one or more different types of substances. Chemical changes occur through chemical reactions and result in substances with different and new chemical and physical properties.

Chemical changes are irreversible in nature and are also known as permanent changes. When chemical responses occur, the molecules are modified and joined by an energy change as new molecules are produced.

Examples of chemical changes: burning of coal, rusting of iron, digestion of food, adding vinegar to baking soda,  germination of seeds, ripening of fruits, cooking an egg, etc.

The given diagram is quite similar to the water formation reaction:

2H₂   + O₂  [tex]\longrightarrow[/tex] 2H₂ O

In which the bond between the hydrogen atoms and oxygen atoms is broken and the formation of the O-H bond, therefore, is a chemical change.

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When all colors of light are absorbed, what do you see?

Black
Orange
Pink
Yellow

Answers

Answer:

Black

Explanation:

hope it helps

have a nice time ..,

How would a descriptive model of Earth's layers be categorized?
a. abstract model
b. prototype model
c. concrete model
d. conceptual model​

Answers

It’s b hope that helped

A descriptive model of Earth's layers can be categorized as prototype model. Hence, option B is correct.

What is a descriptive model?

A descriptive model describes a system or other entity and its relationship to its environment.

The Earth has different compositional and mechanical layers. Compositional layers are determined by their components, while mechanical layers are determined by their physical properties.

The outermost solid layer of a rocky planet or natural satellite. Chemically distinct from the underlying mantle.

Hence, option B is correct.

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When two or more different elements unite chemically, they form a

A) compound
B) mixture
C) metalloid
D) solution

Answers

Answer:

compound ahhhhhhhhhhhhhgh

If you added an excess of sodium phosphate dodecahydrate to 4.512 g barium chloride dihydrate, how many grams of barium phosphate could you synthesize

Answers

Answer:

3.35g of Ba3(PO4)2

Explanation:

The balanced chemical equation is given as;

3 BaCl2 + 2 Na3PO4 → 6 NaCl + Ba3(PO4)2

Fro the reaction;

3 mol of BaCl2 (624g) reacts wth 2 mol of Na3PO4 (327.88g) to form 1 mol of Ba3(PO4)2 (601.93g)

Since Na3PO4 is in excess, the limiting reactant is; BaCl2. It would determine how much of Ba3(PO4)2 is formed.

624g of BaCl2 = 601.93g of Ba3(PO4)2

4.512g of BaCl2= xg of Ba3(PO4)2

x = 4.512g * 601.93g / 624g

x = 3.35g of Ba3(PO4)2

The mass of barium phosphate synthesized is 3.612 g.

The equation of the reaction is;

3 BaCl2.2H2O + 2 Na3PO4.12 H2O → 6 NaCl + Ba3(PO4)2 + 14H2O

Molar mass of barium chloride dihydrate = 244.26 g/mol

The number of moles of barium chloride dihydrate =  4.512 g/244.26 g/mol

= 0.018 moles

From the balanced reaction equation shown;

If 3 moles of barium chloride dihydrate yields 1 mole of  barium phosphate

0.018 moles of  barium chloride dihydrate yields 0.018 moles × 1 mole/3 moles

= 0.006 mole of barium phosphate

Mass of barium phosphate = 602 g/mol × 0.006 mole

= 3.612 g

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Photosynthesis happens in the _____
O: lower epidermis
O: upper epidermis
O: palisade layer
O: spongy layer

Answers

O: palisade layer and please answer the question I am gonna post right now pleaseeee

2. Using the following data, calculate the average atomic mass of magnesium (give your answer to the nearest
.01 ) : Show all work!
Isotope: Mg Percent abundance: 78.70%
24
Isotope: 'Mg Percent abundance: 10.13% 25
Isotope: Mg Percent abundance: 11.17% 26

Answers

Answer: 24.309amu

Explanation:

A element is having atomic number 82. find the number of its protons and electrons

Answers

Answer:

The number of its protons and electrons are 82 each

Explanation:

Atomic no of an element = 82

Atomic no = No of protons

⇒ No of protons = 82

Electrons are negatively charged particle and Protons are positively charged particles.

No of electrons = 82

Hence, the element is Lead with 82 protons and electrons

A sample of a metal has a mass of 23.4 g and a volume of 3.0 mL. What is the sample’s most likely identity?
A. Aluminum (2.8 g/mL)
B. Iron (7.8 g/mL)
C. Copper (8.9 g/mL)
D. Gold (19.3 g/mL)

Answers

Answer:

B. Iron (7.8 g/mL)

Explanation:

23.4/3 = 7.8

7.8g/mL

The identity of a sample of a metal that has a mass of 23.4 g and a volume of 3.0 mL is iron with a density of 7.8g/mL.

How to calculate density?

The density of a substance can be calculated by dividing the mass of the substance by its volume. That is;

Density = mass (g) ÷ volume (mL)

According to this question, a sample of a metal has a mass of 23.4 g and a volume of 3.0 mL. The density of the metal is as follows:

Density = 23.4g ÷ 3mL

Density = 7.8g/mL

Therefore, the identity of a sample of a metal that has a mass of 23.4 g and a volume of 3.0 mL is iron with a density of 7.8g/mL.

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10. What are the upper and lower extremes of
the moisture content of wood?

Answers

The acceptable moisture levels of wood and lumber are in the range of 6% to 8% for interior and 9% to 14% for exterior wood or for building envelope components within constructed assemblies.

calulate the molarity
The first solution contains 0.600 mol of NaOH in 2.10 L of solution.
The second solution contains 10.3 g of NaCl in 675 mL of solution.

Answers

1) 0.286 M NaOH
2) 0.261 M NaCl
Hope this helps :)

Can someone explation for me ? I can’t understand.
Thanks

Answers

Answer:

2 Nitrogen

Explanation:

This is because it says Diammonium Hydrogen Phosphate. Here. (NH4)3PO4 is one way to write this. However, another way to write this is (NH4)2HPO4. There should be in fact two ammonium groups, NH4 and 1 Hydrogen to get 3+ charge to balance the 3- charge from the Phosphate.

How many elements are shown in the diagram below for Hydrogen Peroxide?

Ten
Seven
Four
Two

Answers

Answer:4

Explanation:

4

Photons are emitted as electrons in the atom jump up in energy. true or false?

Answers

Answer:

true

Explanation:

photons are emitted when electrons move from from a lower energy level to a higher energy level

what is the chemical formula for the magnesium ion and the carbonate ion?​

Answers

Answer: The formula for magnesium carbonate is MgCO_3.

Explanation:

What is the law of conservation of matter?
A.Matter can never be changed.
B.Matter can never mix or rearrange.
C.Matter cannot be created or destroyed.
D.matter will always break down.

Answers

Considering the definition of the law of conservation of matter, the law of conservation of matter establishes that matter cannot be created or destroyed (option C).

Law of conservation of matter

The law of conservation of matter holds that, within a closed system, the amount of matter involved in a chemical reaction is constant, meaning a closed system means an environment that isolates the components involved in the reaction from the outside.

In other words, this law establishes that the mass of the reactants consumed is equal to the mass of the products obtained, even though they have been transformed into each other.

In other words, the law of conservation of matter states that matter is neither created nor destroyed during a chemical reaction, it is only transformed.

Summary

In summary, the law of conservation of matter establishes that matter cannot be created or destroyed (option C).

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When ignited, a uranium compound burns with a green flame. The wavelength of the light given off by this flame is greater than that of _____.

Answers

Answer:

Ultraviolet light.

Explanation:

Uranium is a natural radioactive chemical element with the chemical symbol "U" and an atomic number of 92. Uranium is used for generating nuclear fuels which are typically used in powering atomic bombs and nuclear reactors in the field of electricity generation.

When ignited, a uranium compound burns with a green flame. The wavelength of the light given off by this flame is greater than that of ultraviolet light which typically ranges from 100nm to 400nm. Where, nm is represents nanometer.

Basically, when ignited, a uranium compound burns with a green flame having a wavelength of 4.30 x 10^-7m to 5 x 10^-7m.

The circular flow model interacts between which sectors of the economy? Select THREE answers.

Private

Government

Foreign

Tech

Households

Answers

Answer:

2,3,5

Explanation:

Which of the following compounds is the MOST polar?

H−Br

H−F

H−Cl

H−I

Answers

H-F because it has the largest difference in electronegativity which is 2, so it’s the most polar.

Identify the placement of items A-E using the drop-down menus.


A)
⇒No
⇒Yes

B)
⇒No
⇒Yes, when liquid or solution
⇒Yes, when solid

C)
⇒No
⇒Yes

D)
⇒No
⇒Yes

E)
⇒No
⇒Yes

Answers

Answer:

A=no

B= yes when liquid or solution

C=yes

D=no

E=yes

Explanation:

According to the given table, the placement of items A-E are

A) ⇒ No

B) ⇒Yes, when liquid or solution

C) ⇒Yes

D) ⇒No

E) ⇒Yes

What is conductivity and Malleability?

Malleability - Those metals that can be beaten into thin sheets with a hammer or any heavy object. For example - Cu, Au etc

Conductivity - Conductivity is the measure of the ease at which an electric charge or heat can pass through a material. For example - Metals are good conductors of heat and electrolytic solution is conductors of electricity.

Therefore, according to the given table, the placement of items A-E are

A) ⇒ No

B) ⇒Yes, when liquid or solution

C) ⇒Yes

D) ⇒No

E) ⇒Yes

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What is the velocity of a wave?

A. How much energy the wave has
B. How quickly the wave travels
C. The distance between two wave peaks
D. The distance between the high and low points of the wave

Answers

The answer is b. How quickly the wave travels

Which of the following is an example of a pure substance?
A. beer
C. halo-halo
B. ethyl alcohol
D. silver spoon​

Answers

Sliver spoon is an example of a pure substance

a typical baseball has a mass of 350g and takes up a volume of .780L. what is the density of a baseball in g/l and g/ml?

Answers

Answer:

449 g/L

0.449 g/mL

Explanation:

Step 1: Given data

Mass of a typical baseball (m): 350 gVolume of a typical baseball (V): 0.780 L

Step 2: Calculate the density (ρ) of the baseball in g/L

The density is equal to the quotient between the mass and the volume.

ρ = m / V

ρ = 350 g / 0.780 L

ρ =449 g/L

Step 3: Convert ρ from "g/L" to "g/mL"

We will use the conversion factor 1 L = 1000 mL.

449 g/L × (1 L/1000 mL) = 0.449 g/mL

14. Identify the type of reaction: Pb + 2 AgCl → 2 Ag+ PbCl2
a. Combination/synthesis
b. Decomposition
c. Double replacement
d. Single replacement

Answers

Single displacement!

Complete each statement by choosing the correct answer from the drop-down menu.


are the types of muscle tissue found in the human body.
Muscle cells are specialized to

are the two specialized proteins found in muscle.Muscle Tissue

Answers

Answer:

smooth, skeletal, cardiac

contract

actin and myosin

Explanation:

edge

Answer:

The correct answers are

smooth, skeletal, cardiac

contract

actin and myosin

What was the average speed of the truck for this trip?

Answers

Answer:

31.67 mph

Explanation:

To calculate the average speed of the truck, we must first obtain the total distance travelled by the truck followed by the total time taken for the truck to cover the distance travelled.

The following data were obtained from the question include:

Total distance) = 30 + 45 + 50 + 65 = 190 miles

Total time = 1 + 2 +1 +2 = 6 hours

Average speed =.?

Average speed = Total distance / Total time

Average speed = 190 /6

Average speed = 31.67 mph

Therefore, the average speed of the truck is 31.67 mph

PLEASE HELP ASAP‼️ Which of the following elements has the highest metallic character
A. Zt
B. Rh
C. Hf
D. Co​

Answers

Answer: C

Explanation:

Balance the following equation. ZnCl2 + (NH4)3PO4 ->__Zn3(PO4)2 + NHACI​

Answers

Answer:

3ZnCl2 + 2(NH4)3PO4 → Zn3(PO4)2 + 6NH4Cl

Explanation:

Zinc Chloride + Tribasic Ammonium Phosphate = Zinc Phosphate + Ammonium Chloride

Reaction Type

Double Displacement (Metathesis)

Reactants

Zinc Chloride - ZnCl2

Zinc(II) Chloride Zinc Chloride, Anhydrous Dichlorozinc Butter Of Zinc Zinc Chloride Zn-65

Molar Mass of ZnCl2 Oxidation State of ZnCl2

Tribasic Ammonium Phosphate - (NH4)3PO4

Ammonium Phosphate

Molar Mass of H12N3O4P Oxidation State of H12N3O4P

Products

Zinc Phosphate - Zn3(PO4)2

Zinc(II) Phosphate

Molar Mass of O8P2Zn3 Oxidation State of O8P2Zn3

Ammonium Chloride - NH4Cl

Amchlor Ammoneric Ammonium Muriate Darammon Sal Ammonia Sal Ammoniac Salammonite Salmiac

Molar Mass of ClH4N Oxidation State of ClH4N

3.) Why is argon (Ar) larger than neon (Ne)?​

Answers

Answer: Here u go!

Explanation:

The electron cloud of argon is thus larger and more polarized, able able to express mawr inter molecular forces Vander Waals forces, which results in a higher boiling point due to these increase forces. Due to this, the boiling point of argon is higher are gone. We can see its boiling point is 87.2 Kelvin's, whereas a neon and spoiling point is 24.5.

Hope this helps!

Explanation:

Argon has an atomic number of 18, while neon has an atomic number of 10.

The atomic radius is comprised of the atom’s nucleus and electron cloud. As you go down on the periodic table, the effective nuclear charge decreases. This results in more screening of the electrons

from the nucleus (decreasing the attraction between the nucleus and the electrons) resulting in a larger atomic radius.

However, because they’re both noble gasses, the size difference in this case can be easier described by the number of particles in each atom.

Argon has 18 protons, 18 electrons and 22 neutrons.

Neon has 10 protons, 10 electrons and 10 neutrons.As you can see, argon has more “stuff.”

The increase in protons and electrons in particular results in a larger electron cloud, which means a much larger atomic radius than in neon.

i hope it helps u :)

What are the four main types of tissues in the human body?

Answers

connective tissue, epithelial tissue, muscle tissue, and nervous tissue.

Answer:

epithelial tissue, connective tissue, muscle tissue, and nerve tissue

Explanation:

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Which historical figure was inspired by Christian teachings and the idea of "theKingdom of God"?A. AkhenatenB. SocratesC. Martin Luther KingD. None of the above The Nile River was important to Egypt and Nubia because it... 1. Jen went scuba diving. She makes the first stop on her descent at 45 meters below thesurface of the water. From that point she dives down further, stopping every 10 meters. Ifshe makes 3 additional stops, at what depth will she be? If the place these marbles in a bag close your eyes and choose a marble what is the probability that it will be pink?