Please help I need a answer to both

Please Help I Need A Answer To Both

Answers

Answer 1

Hi , I’m really sorry because I just have the first question... so here it is :

So it is 0.52 mol .

Have a nice day .

Please Help I Need A Answer To Both
Please Help I Need A Answer To Both

Related Questions

Please help
It’s super quick

Answers

Answer:

1. a

Explanation:

2. c

Answer:

1 is A number two is C

What is the name of the process that is used to clean up environmental waste and how does it work?

Answers

Answer:

Environmental cleanup includes removal of heavy metals and other toxic contaminants from the environment and the process is called remediation.

Write the net ionic equation for the acid-base reaction
PH3(aq) + HCl(aq) - PH4Cl(aq)

Answers

Explanation:

i dont understand dont you already have the equation?

The net ionic equation for the acid-base reaction PH[tex]_3[/tex](aq) + HCl(aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]Cl(aq) is PH[tex]_3[/tex](aq) + H⁺ (aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]⁺ .

What is net ionic equation?

Chemical reaction equations can be written in a variety of ways. Unbalanced chemical equations, which identify the species involved, balanced chemical equations, which identify the number and type of species, molecular equations, that also express compounds as molecules rather than component ions, and net ionic equations, which only address the species which contribute to a reaction, are some of the most popular.

A chemical equation for just a process known as the net ionic equation only includes the species that are really involved in the reaction.

PH[tex]_3[/tex](aq) + HCl(aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]Cl(aq)

PH[tex]_3[/tex](aq) + H⁺ (aq)  + Cl⁻ (aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]⁺ (aq)  + Cl⁻ (aq)

PH[tex]_3[/tex](aq) + H⁺ (aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]

Therefore,  the net ionic equation for the acid-base reaction is PH[tex]_3[/tex](aq) + H⁺ (aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]⁺ .

To learn more about  net ionic equation, here:

https://brainly.com/question/29299745

#SPJ6

Why is it necessary to add concentrated HCl, then water, rather than a solution of HCl to the eudiometer tube

Answers

The reaction between concentrated acid and water can release a lot of heat. If a little water is added to a larger amount of acid, the heat can cause the small amount of water to boil very rapidly which then spatters some acid. ... It is recommended that acid should be added to water and not water to acid.

If we add water to a concentrated acid, then the solution may boil very violently, splashing concentrated acid. If add acid to water, the solution that forms is very dilute and a small amount of heat is released.

Why do we add acid to water?

When a strong acid is poured into water, it flows down the flask and mixes much better, so no boiling takes place. The addition of water to acid forms an extremely concentrated solution of acid initially. A large amount of heat is released and the solution may boil very violently, splashing concentrated acid out of the beaker and all this because the reaction is exothermic in nature.

The reason this takes place is due to a large amount of energy liberated in the hydration reaction of concentrated ions. Therefore, we add acid to water dropwise for the dilution with constant stirring and not water to acid directly.

If we add water to acid, then an exothermic reaction occurs and the solution may boil very violently. To form the dilute solution of any strong acid, you should add acid to water and the small amount of heat released is not sufficient to vaporize and spatter it.

Learn more about dilution of acid, here:

https://brainly.com/question/

#SPJ2

Which of the following aqueous solutions has the lowest pH? Why?
a. 0.1 M HCl;
b. 0.1 M acetic acid (pKa = 4.86);
c. 0.1 M formic acid (pKa = 3.75

Answers

Answer:

HCI

Explanation:

The solution with the lowest pH is HCI with a pH value of 1. It is understood that it is more acidic because it is a strong acid.

28. A gas exerts pressure at 5atm at 300K. What is the pressure of the gas at 600K?
a) 1 atm b) 10 atm c).1 atm d) 100 atm

Answers

B the atm hehsjskkakajahhajajajajjajajajsjsjjsjsjsnsnnsns

What volume of a 0.155 M potassium hydroxide solution is required to neutralize 25.7 mL of a 0.388 M hydrobromic acid solution

Answers

Answer: Therefore, the volume of a 0.155 M potassium hydroxide solution  is 56.0 ml

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.

According to the neutralization law,

[tex]n_1M_1V_1=n_2M_2V_2[/tex]

where,

[tex]M_1[/tex] = molarity of [tex]HBr[/tex] solution = 0.338 M

[tex]V_1[/tex] = volume of [tex]HBr[/tex] solution = 25.7 ml

[tex]M_2[/tex] = molarity of [tex]KOH[/tex] solution = 0.155 M

[tex]V_2[/tex] = volume of [tex]KOH[/tex] solution = ?

[tex]n_1[/tex] = valency of [tex]HBr[/tex] = 1

[tex]n_2[/tex] = valency of [tex]KOH[/tex] = 1

[tex]1\times 0.338\times 25.7=1\times 0.155\times V_2[/tex]

[tex]V_2=56.0ml[/tex]

Therefore, the volume of a 0.155 M potassium hydroxide solution  is 56.0 ml

Explain how Bohr's model built on the ideas of Einstein and Planck.

Answers

Explanation:

Bohr built on Nicholson's idea by adopting the requirement that the angular momentum can have only certain discrete values related to Planck's constant. However Bohr's atom has many orbits for the electrons.

Which temperature is warmest
A. 0°C
B. 273 K
C. 32°F
D. 30°C​

Answers

I think your answer will be B. 273 k

Answer:

your answer should be B.273 K

Explanation:

The critical resolved shear stress for a metal is 35 MPa. Determine the maximum possible yield strength (in MPa) for a single crystal of this metal that is pulled in tension.

Answers

Answer:

The maximum possible yield strength for a single crystal is 70 MPa.

Explanation:

To find the maximum possible yield strength for a single crystal we need to use the following equation:

[tex]\sigma_{y} = \frac{\tau_{CRSS}}{m_{max}}[/tex]

Where:

[tex]m_{max}[/tex] is the maximum value for Schmid factor

[tex]\tau_{CRSS}[/tex] is the critical resolved shear stress = 35 MPa

[tex] \sigma_{y}[/tex] is the yield strength =?    

The Schmid factor is given by:

[tex]m = cos(\phi)cos(\lambda)[/tex]

And its maximum value is obtained when λ = 45° and Φ = 45°, so:

[tex] m = cos(45)cos(45) = 0.5 [/tex]

Finally, the maximum possible yield strength is:

[tex]\sigma_{y} = \frac{\tau_{CRSS}}{m_{max}} = \frac{35 MPa}{0.5} = 70 MPa[/tex]

Therefore, the maximum possible yield strength for a single crystal is 70 MPa.

I hope it helps you!                                                                                  

How much heat would be required to convert 5.31 mol of a pure substance from a liquid at 40.0°C to a gas at 113.0°C?

Answers

Answer:

Q = 7.7 KJ

Explanation:

The complete question carries the following data:

Specific Heat Capacity of Liquid State = C(l) = 1.45 J/mol.°C

Specific Heat Capacity of Gaseous State = C(g) = 0.65 J/mol.°C

Boiling Temperature = Tb = 88.5°C

Heat of Vaporization = ΔH(vap) = 1.23 KJ/mol

Now, first we calculate the heat required (Q₁) to raise he temperature to boiling point:

Q₁ = n*C(l)*ΔT₁

where,

n = no. of moles = 5.31 mol

ΔT₁ = Temperature difference from 40°C to Tb = 88.5°C - 40°C = 48.5°C

Therefore,

Q₁ = (5.31 mol)(1.45 J/mol.°C)(48.5°C)

Q₁ = 373.4 J = 0.37 KJ

Now, we calculate the heat required (Q₂) to change its phase:

Q₂ = nΔH(vap)

Q₂ = (5.31 mol)(1.23 KJ/mol)

Q₂ = 6.53 KJ

Now, we calculate the heat required (Q₃) to raise he temperature to boiling point:

Q₃ = n*C(g)*ΔT₃

where,

n = no. of moles = 5.31 mol

ΔT₃ = Temperature difference from Tb to 113°C = 113°C - 88.5°C = 24.5°C

Therefore,

Q₃ = (5.31 mol)(0.65 J/mol.°C)(24.5°C)

Q₃ = 84.5 J = 0.08 KJ

So, the total heat required to convert 5.31 mol of this pure substance from a liquid at 40°C to a gas at 113°C is:

Q = Q₁ + Q₂ + Q₃

Q = 0.37 KJ + 6.53 KJ + 0.08 KJ

Q = 7.7 KJ

The total heat required to convert the pure substance from liquid to gas at the given temperature is 814 J.

The given parameters;

molar heat capacity of liquid, C(l) = 1.45 J/mol.⁰Cmolar heat capacity of gas, C(g) = 0.65 J/mol.⁰C

The total heat required to convert the pure substance from liquid to gas at the given temperature is calculated as follows;

[tex]Q = nc_l \Delta \theta + nc_g \Delta \theta \\\\ \Delta \theta = (113 - 40) = 73^0 C \\\\Q = (5.31 \ mol \times 1.45 \frac{J}{mol .\ ^0C} \times 73\ ^0C) + (5.31 \ mol \times 0.65 \frac{J}{mol .\ ^0C} \times 73 \ ^0C)\\\\Q = 814 \ J[/tex]

Thus, the total heat required to convert the pure substance from liquid to gas at the given temperature is 814 J.

"Your question is not complete, it seems to be missing the following information;"

How much heat would be required to convert 5.31 mol of a pure substance from a liquid at 40.0°C to a gas at 113.0°C? (molar heat capacity of liquid, C(l) is 1.45 J/mol.⁰C and molar heat capacity of gas, C(g) is 0.65 J/mol.⁰C).

Learn more here:https://brainly.com/question/8428922

Question in picture!!!!!!

Answers

Answer:

6 atoms

Explanation:

What are some foods that bacteria helps in the production of?

Answers

Answer:

yeasts, moulds, bread, beer, wine, ...

Explanation:

What volume of 0.150 M 2 M Li2S solution is required to completely react with 120 mLmL of 0.150 M Co(NO3)2 MCo(NO3)2

Answers

Answer:

Explanation:

M1V1=M2v2

M1=0.150M

M2=0.150M

V2=120*10^-3

V1=M2V2/M1

V1=0.150*120*10^-3/0.150

V1=0.12

0.12 mL volume of 0.150M 2M Li₂S solution is required to completely react with 120 mL of 0.150M Co(NO₃)₂ MCo(NO₃)₂.

What is the relation of volume with molarity?

With M1 and M2 representing the molarity of the solutions, expressed as mol/L or M, and V1 and V2 representing their respective volumes, this calculator may be used to calculate a missing number for the dilution equation.

A solution's concentration is determined by multiplying its volume by its molarity (M1V1 = M2V2) On both sides of the equation, the units should stay the same.

Here

M₁V₁=M₂V₂

M₁=0.150M

M₂=0.150M

V₂=120 × 10⁻³

V₁=M₂V₂/M₁

V₁=0.150 × 120 × 10⁻³/0.150

V₁=0.12.

Therefore, 0.12 mL volume of 0.150M 2M Li₂S solution is required to completely react with 120 mL of 0.150M Co(NO₃)₂ MCo(NO₃)₂.

Read more about volume and molarity, here

https://brainly.com/question/4172228

#SPJ2

What most likely to cuase the rate of a chemical reaction to increase

Answers

Answer:

An increase on temperature.

Explanation:

Answer: adding a catalyst or increasing temperature

Explanation:

What mass is contributed by Br-79?

Answers

Answer:

Calculate the mass of BR -79? Bromine has 2 naturally occurring isotopes (Br-79 and Br-81) and has an atomic mass of 79.904 amu

Explanation:

if i get this wrong srry

What is the density of a glass piece that has mass of 18 g and a volume of 24 mL?

Answers

Answer:

The answer is 0.75 g/mL

Explanation:

The density of a substance can be found by using the formula

[tex]density = \frac{mass}{volume} \\ [/tex]

From the question we have

[tex]density = \frac{18}{24} = \frac{3}{4} \\ [/tex]

We have the final answer as

0.75 g/mL

Hope this helps you

1. With the aid of a Hess cycle, determine the enthalpy of the decomposition reaction of sodium nitrate, NaNO3 to sodium nitrite, NaNO2 and oxygen, O2. [5]

Enthalpy of formation of NaNO3 = -468 kJ/mol
Enthalpy of formation of NaNO2 = -369kJ/mol

Answers

Answer:

Explanation:

2NaNO₃ = 2NaNO₂ + O₂

NaNO₃    =     NaNO₂   +    1/2 O₂

- 468 kJ           -369 kJ           0  kJ

enthalpy of decomposition reaction

= - 369 - ( - 468 ) kJ

= 99 kJ / mol .      

Name 2 ways heat can be transferred through convention.

Answers

Answer:

Heat can travel from one place to another in three ways: Conduction, Convection and Radiation. Both conduction and convection require matter to transfer heat. If there is a temperature difference between two systems heat will always find a way to transfer from the higher to lower system.

Explanation:

What is the oxidation number of P in PF6−?

Answers

Answer:

P = +5

Hope it helps!

Two moles of acetyl chloride was mixed with two moles of dimethylamine. After the reaction is complete, what species can be found in the mixture

Answers

Answer:

See explanation

Explanation:

The reaction is shown in the image attached. This reaction occurs by a carbocation (ionic) mechanism.

The lone pair on the nitrogen atom attacks the carbocation leading to the formation of the product as shown in the image attached.

Since the reaction occurs in a 1:1 ratio, two moles of reactants yields two moles of product.

Which of the following conclusions about the two intermolecular forces is correct? X represents London dispersion forces, and Y represents ion-dipole forces. X represents dipole-dipole forces, and Y represents ion-dipole forces. X represents hydrogen bonding, and Y represents dipole-dipole forces. X represents London dispersion forces, and Y represents dipole-dipole forces.

Answers

Answer:

X represents London dispersion forces, and Y represents dipole-dipole forces.

Explanation:

i will give the first person brainliest! please helppp

Answers

okay so the  Answer is c

When is a chemical equation considered balanced

Answers

Answer:

If each side of the equation has the same number of atoms of a given element, that element is balanced. If all elements are balanced, the equation is balanced.

Explanation:

An ice cube melts in the hot sun. Is this exothermic or endothermic and
why?

Answers

Answer:

Endothermic

Explanation:

In order to melt the ice cube, heat is required, so the process is endothermic. Endothermic reaction In an endothermic reaction, the products are higher in energy than the reactants. Therefore, the change in enthalpy is positive, and heat is absorbed from the surroundings by the reaction.


is the movement of particles from an area of higher concentration to an area of lower concentration

Answers

Answer:

The answer is Diffusion.

Answer:

Hypertonic

Explanation:

What is the Atomic number of 12

Answers

Answer:

atomic number of 12 is MG

Explanation:

Magnesium

Calculate the number of moles of solute in 431.9 L of 0.722 M sodium cyanide.

Answers

Answer:

[tex]312 \ mol \ solute[/tex]

General Formulas and Concepts:

Chemistry

Molarity = moles of solute / liters of solution

Explanation:

Step 1: Define variables

M = 0.722

L = 431.9

m = x

Step 2: Solve for x

Substitute:                   [tex]0.722 \ M=\frac{x \ mol}{431.9 \ L}[/tex]Isolate x:                      [tex]311.832=x \ mol[/tex]Rewrite:                       [tex]x=311.832 \ mol[/tex]

Step 3: Check

Our smallest sig figs is 3. Follow sig figs rules.

[tex]311.832 \ mol \approx 312 \ mol \ solute[/tex]

A 1.00 gram sample of which of the following compounds contains the greatest mass of oxygen? And explain.

1. K2O2
2. Na2O
3. BeO

Answers

Answer:

BeO will have the greatest mass composition of oxygen

Explanation:

To solve this problem, we would find the mass composition of oxygen in each of the given sample.

To find this mass composition, let us derive the molecular mass of the given species;

  K₂O₂ = 2(39) + 2(16) = 110g/mol

  Na₂O = 2(23) + 16 = 62g/mol

   BeO = 9 + 16  = 25g/mol

Now; we know that mass of each sample is 1g;

mass composition of O in K₂O₂ = [tex]\frac{32}{110}[/tex] x  1= 0.29g

mass composition of O in Na₂O = [tex]\frac{16}{62}[/tex] x 1 = 0.26g

mass composition of O in BeO = [tex]\frac{16}{25}[/tex] x 1 = 0.64g

We can see that BeO will have the greatest mass composition of oxygen.

The mass composition of oxygen has been highest in BeO. Thus, option 3 is correct.

The molecular mass has been the mass of each element that has been present in the compound. The molecular mass of given compounds have been:

[tex]\rm K_2O_2[/tex] = 2(mass of K) + 2(mass of O)

= 2 (39) + 2 (16)

= 110 g/mol

[tex]\rm Na_2O[/tex]= 2(mass of N) + mass of O

= 2 (23) + 16

= 62 g/mol

BeO = mass of Be + mass of O  

= 9 + 16

= 23 g/mol

The mass composition of oxygen in 1 gram of the following compounds have been:

Mass composition = [tex]\rm \dfrac{Mass\;of\;Oxygen}{Molecular\;mass\;of\;compound}\;\times\;weight\;of\;sample[/tex]

[tex]\rm K_2O_2[/tex] = [tex]\rm \dfrac{32}{110}\;\times\;1\;gram[/tex]

[tex]\rm K_2O_2[/tex] = 0.29 grams

[tex]\rm Na_2O[/tex] = [tex]\rm \dfrac{16}{62}\;\times\;1\;gram[/tex]

[tex]\rm Na_2O[/tex] = 0.26 grams

BeO = [tex]\rm \dfrac{16}{23}\;\times\;1\;gram[/tex]

BeO = 0.64 grams.

The mass composition of oxygen has been highest in BeO. Thus, option 3 is correct.

For more information about the mass composition, refer to the link:

https://brainly.com/question/13531044

How does Newton’s second law apply to the golf tee balanced on the hoop? How does Newton’s second law apply to the golf tee when the hoop is pulled away?

please answer asap

Answers

Answer:

The law applies and it tells us that the object has constant velocity.

Explanation:

Using the second law of motion the momentum remains constant. Therefore, the velocity of the object is constant.

There are total three laws of newtons, first law of newtons, second law of newton and third law of newton. Therefore, when a golf club is subjected to an imbalanced force, its velocity changes, which is according to newton’s second law.

What is newton's second law?

According to Newton's Second Law of Motion, acceleration (gaining speed) occurs when a force acts on a mass (object). Riding a bicycle is a great example of this rule of motion in action. The mass is represented by your bicycle. The force is generated by your leg muscles pulling on the pedals of your bicycle.

The ball remains balanced on the tee due to the balanced forces of gravity downhill and upward. Force equals mass multiplied by acceleration (f=ma). When a golf club is subjected to an imbalanced force, its velocity changes.

Therefore, when a golf club is subjected to an imbalanced force, its velocity changes, which is according to newton’s second law.

To know more about newton's second law, here:

https://brainly.com/question/13447525

#SPJ2

Other Questions
A zygote is the result of which life cycle process in spermatophytes?a) germinationb) fertilizationc) pollinationd) cell respiration figure out the slope of the line that passed through each pair of points (4,-11) and (7,-8) PLEASE HELP ME!! I just need some ideas please!!Write a multiparagraph essay of at least five hundred words that answers the question: How do Crane and Lincoln treat the subject of the Civil War in each of their respective texts?Construct a comparison outline to organize your ideas. Incorporate these ideas into your writing.Submit your outline and the final draft of your essay. Your essay should be at least 500 words in length. What are some good insultsAlso so this don't get deleted: What is an exponent? plzzzz help meeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee What are the two factors that can affect the current in a wire whats the point on the graph 3. Why was the United States involved in the Barbary Wars? * I think this is my last one! Will give Brainliest! DUE TODAY!!!Will give everything good and will make smartest answer WITH WORK Brainliest. Which table represents a linear function?y1722114312612413815N X717492.9611312813415 The admission fee to an amusement park is $27. It costs an additional d dollars to rend a locker to hold your belongings. The total cost for 10 people to enter the amusement park and each rent a locker is $330. How much does it cost for one person to rent a locker? Ahhh! Such a beautiful day, uh (Yeah)The sun's shining in a beautiful way, uh (Whoo)Gonna take a shower, brush my teeth andLife is ultimately meaninglessUhh... Uhh...But I'll get out of the houseGet on the road, top down, hands outPut on my favorite song and nod to the rhythmThe planet's being destroyed by your carbon emissionsBut I- I-, I'll head to classTry my best on every test 'til I passAnd my grades are screaming in my face, hey98 percent of what you learn is a wasteI get to hang out with all my friends (Yeah)My friends are the friendliest friendsCan't think of a better way to spend my timeYour brain is flawed, and all your friends will dieNever mind!I'm alive in the greatest nation!So proud of the exploitation of nativesThis graceful bird means freedom for allTell that to the slaves, and bald eagles aren't baldI can live in the moment, milk every secondAt any time you could get clinical depressionBut I'll just be happy, no matter what's in storeIt's quite genetic, and we have no cureUh, at leastWe are youngNot for longLife is funIt only goes downhillWe gotta make the most of it! Make the most of it!Or you'll regret itWe are youngFor nowLife is funFor some peopleWe gotta make the most of it! Make the most of it!Good luckWoo! I got a brand new job today! (Yeah)Doin stuff that'll help the economy (Uh)I'll save money and buy things at the storeBanks can crash and capitalism is flawedAnd it's all because of my hard workAnd the thousand advantages you lucked into at birthI put a lotta effort in my resume!Good thing you don't have a black person's nameI'm proud to be a functioning member of societyFinally, I can be the citizen I dream to bePart of the community, contribute with my taxWhat could possibly stop me?The shrinking middle classI've at least got a nice stable jobUntil it's outsourced to China or replaced by a robotOH GOD! Well, then I could relax a bitYou'll be empty with nothing to distract from itBut man, I'm a passionate graduateI can be different, and I have a career paths to pick fromI could be a rapper or an animator if I'm luckyNeither of those will make you happy, trust meI'm able to choose what I pursue (Yeah)You're a slave to people born richer than youThen screw it, I'll keep going inThen I'll party on the weekend and sing, no, oh, oh ohThanks to autotuneWe are youngNot for longLife is funIt only goes downhillWe gotta make the most of it! Make the most of it!Or you'll regret itWe are youngWe still dieLife is funUntil you dieWe gotta make the most of it! Make the most of itBecause you'll dieLife is a wonderYou'll never know the answerNature is a miracleNatural disastersIt's good to be aliveYou could wake up with cancerBut I'm healthyHealthy people still get cancerI love this showIt's the last episodeThe sun is shiningIt's going to explodeEvery species is beautiful and unique, thoughChildren have malaria thanks to mosquitoesI met a cute girl with a ponytailStatistically that relationship is going to failI have a wonderful family, it's like no otherYou're not special, and one day you'll bury your motherNo matter what, I can find a home!We, Will All, Die, AloneThere's amazing potential in every human on earthThere's no escaping the heat death of the universeI don't have to live life based on negative partsNo matter how bad they are, they're just thoughtsYeah, that's fairWait, really?Yeah that seems reasonableWait, wait, wait, wait but you were just telling me to-Whatever man, I dunno, live your life how you wantI'm not forcing you to do anything, I'm just sayingOh...Well in that case...We are young!Life is fun!We gotta make the most of it! Make the most of it!We are young!Life is fun!We gotta make the most of it! Make the most of it!Enjoy it while it lasts Andre and Diego were each trying to solve `2x+6=3x-8`. Describe the first step they each make to the equation.The result of Andre's first step was `-x+6=-8`. On the variable costing income statement, the figure representing the difference between manufacturing margin and contribution margin is the: a.variable cost of goods sold b.fixed manufacturing costs c.variable selling and administrative expenses d.fixed selling and administrative expenses what asian country was closed to the u.s. for more than 200 years A. China b. Hawaii c. Japan PLEASE HELP! FIRST RATIONAL ANSWER GETS BRAINLIEST! PLEASE EXPLAIN 30 points! to who helps me out HURRY I NEED HELP SOONZola and her friends are going bowling. The bowling alley charges each person a $14 fee to rent shoes, plus $4.50 per game.Which equation represents the cost, y, for each friend to go bowling in terms of the number of games played, x?a. y=4.50x +14b. y= -14x - 4.50c. y= -4.50x - 14d. y= 14x + 4.50 HELP!!! Parallel Line Proofs In the diagram, AB= DC and AC= DB. Why does DBC = ACB?