A container of oxygen gas is at STP. If this sample is put into an oven at 280 C, what would its pressure be, in atmospheres?

Answers

Answer 1

Explanation:

Step 1:

Data obtained from the question. This include the following:

Initial pressure (P1) = 1atm

Initial temperature (T1) = 0°C = 0°C + 273 = 273K

Final temperature (T2) = 280°C = 280°C + 273 = 553K

Final pressure (P2) =...?

Step 2:

Determination of the new pressure of the gas.

Since the volume of the gas is constant, the following equation:

P1/T1 = P2/T2

will be used to obtain the pressure. This is illustrated below:

P1/T1 = P2/T2

1/273 = P2 / 553

Cross multiply

273x P2 = 553

Divide both side by 273

P2 = 553/273

P2 = 2.03atm

Therefore, the new pressure of the gas will be 2.03atm

Answer 2

Answer:

[tex]\boxed {\boxed {\sf P_2=2.03 \ atm}}[/tex]

Explanation:

We are concerned with the variables of temperature and pressure, so we use Gay-Lussac's Law, which states the temperature of a gas is directly proportional to the pressure. The formula is:

[tex]\frac{P_1}{T_1}=\frac{P_2}{T_2}[/tex]

We know that the container of gas begins at standard temperature and pressure (STP). This is 1 atmosphere of pressure and 273 Kelvin.

[tex]\frac { 1 \ atm}{ 273 \ K} = \frac{P_2}{T_2}[/tex]

We know the gas is put into an oven at 280 degrees Celsius. We can convert this to Kelvin.

K= °C + 273.15 K= 280 +273.15K= 553.15

[tex]\frac { 1 \ atm}{ 273 \ K} = \frac{P_2}{553.15 \ K}[/tex]

We are solving for the new pressure, so we must isolate the variable P₂. It is being divided by 553.15 Kelvin. The inverse of division is multiplication, so we multiply both sides by 553.15 K

[tex]553.15 \ K *\frac { 1 \ atm}{ 273 \ K} = \frac{P_2}{553.15 \ K} * 553.15 \ K[/tex]

[tex]553.15 \ K *\frac { 1 \ atm}{ 273 \ K}= P_2[/tex]

The units of Kelvin cancel.

[tex]553.15 *\frac { 1 \ atm}{ 273 }= P_2[/tex]

[tex]2.02619047619 \ atm = P_2[/tex]

Rounded to the nearest hundredth:

[tex]2.03 \ atm \approx P_2[/tex]

The new pressure is approximately 2.03 atmospheres.


Related Questions

The reaction of an acid and a base produce water and a

Answers

Answer:

The answer is " salt".

Explanation:

Hey there!

When any acids and base react with eachother, they forms water and respective salts.

For example:

HCl + NAOH = NACl + H2O.

Hope it helps!

Why are polar gases, such as H2O and NH3, more likely to deviate from the ideal gas behaviors described by the kinetic molecular theory? (3 points)

Question 4 options:

1)

The density of these gases is high, increasing the number of collisions and reducing their elasticity.

2)

The fluidity of these gases is high, resulting in a higher average kinetic energy.

3)

The particles have a significant volume, reducing the space between the moving particles.

4)

The particles have high intermolecular forces, reducing the elasticity of their collisions.

Answers

Answer:

The particles have high intermolecular forces, reducing the elasticity of their collisions.

Explanation:

4.) which organic compound has five carbon atom with at least one double bond?

O pentyne
O pentene
O pentane
O butene

Answers

Answer:

The answer is pentene.

Explanation:

The nomenclature for an organic compound with 5 carbon atoms will have a  -pent prefix.

An organic compound with at least one double bond will have alkene suffix, which is -ene.

Thus, the nomenclature for an organic compound that has 5 carbon atoms with at least one double bond will be pentene.  

Help plz!
--------------
Objects that are very dense, such as iron, can decrease their density by spreading their mass out over
A. a larger mass
B. a larger volume
C. a larger density
D. a larger object

Answers

Answer:

hi! I hope your having a awesome day

Explanation:

HELP HELP!!!Calculate the mass of 3.4 moles of nitric acid (HNO3) Explain the process or show your work by including all values used to determine the answer
NO LINKS

Answers

Answer:

The mass of nitric acid is, 214.234 grams.

Solution: Given,

Moles of nitric acid = 3.4 moles.

Mole is 3.4 which is  substance.

どういたしまして。

お役に立てばよいのですが。

ウェブサイト の ひょうか を して

ください。

Question 1
Part A
Describe the sequence of adding ingredients to make the recipe for condensed tomato soup. To mix the ingredients, you have an industrial-sized vat with a capacity of 800 L. You also have the ability to heat what is in the vat and/or stir the vat, both of which require energy and therefore, cost you money. Focus on the fact that the manufacturing process should be time efficient and cost efficient in terms of energy use. Be sure to refer to the solubility charts or graphs that you find for salt and sugar during your research. Finally, presume that the tomato powder has low solubility which is not temperature dependent.

Part B
What changes could be made to optimize the manufacturing process?

Answers

Answer:

Part A:

"360 grams of NaCl can be dissolved in 1 L water. So, 2000 grams sugar can be dissolved in 1 L water then we can say that the solubility of salt is lesser in water as to sugar and both heightened by increasing the temperature. If we make a batch of 800 L we can add sugar, 1600 kg at 25 0c. We can add salt is 288 kg at 25 0c and the ingredient tomato is having low solubility."

Read more at Answer.Ya.Guru – https://answer.ya.guru/questions/8061-describe-the-sequence-of-adding-ingredients-to-make-the-recipe.html

Part B:

'Manufacturers can generate new value minimize cost and increase operational stability by focusing on 4 broad areas; Management, Supply Circle, Product Design, and Value Recovery.'

Read more at Answer.Ya.Guru – https://answer.ya.guru/questions/2807911-what-changes-could-be-made-to-optimize-the-manufacturing-process.html

In order to make tomato soup, the salt NaCl is first added, then followed by sugar and finally the tomato powder.

What are the ingredients required in making tomato soup?

Tomato soup is made of the following ingredients:

Tomato powder salt, NaClsugar

In order to make tomato soup, the salt NaCl is first added, then followed by sugar. This is to ensure increase in the boiling point of water and to reduce the heating time of the tomato soup.

The solution is heated to induce more dissolution if solute and finally the tomato powder is added.

In order to optimize the manufacturing process, changes should be made in the design, supply and composition of the soup.

Therefore, an optimized manufacturing process will reduce cost of production.

Learn more about tomato soup at: https://brainly.com/question/21475711

The pressure of a certain amount of gas in a 1.25 L balloon is 760 torr. What would the pressure of that balloon be if it's volume was increased to 2.15 L?

Answers

Answer:

440 torr

General Formulas and Concepts:

Chemistry

Ideal Gas Law

Boyle's Law: P₁V₁ = P₂V₂

P₁ is pressureV₁ is volumeP₂ is new pressureV₂ is new volume

Math

Pre-Algebra

Order of Operations: BPEMDAS

Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to Right  

Equality Properties

Multiplication Property of Equality Division Property of Equality Addition Property of Equality Subtraction Property of Equality Explanation:

Step 1: Define

Identify

[Given] V₁ = 1.25 L

[Given] P₁ = 760 torr

[Given] V₂ = 2.15 L

[Solve] P₂

Step 2: Solve for P₂

Substitute in variables [Boyle's Law]:                                                              (760 torr)(1.25 L) = P₂(2.15 L)Multiply:                                                                                                             950 torr · L = P₂(2.15 L)[Division Property of Equality] Divide 2.15 L on both sides:                          441.86 torr = P₂Rewrite:                                                                                                             P₂ = 441.86 torr

Step 3: Check

Follow sig fig rules and round. We are given 2 sig figs as our lowest.

441.86 torr ≈ 440 torr

HELP PLEASE

1. Locations where volcanoes form far from plate boundaries are called
A. islands
B. hot spots
C. divergent zones

Answers

the answer is b. hot spots

90 grams of NaNO3 were added to solution at 10 degrees Celsius. What type of solution was formed?

Answers

Answer:

friend me on here and imma send you the link Explanation:

pleassseeeee i’ll give brainiest!!!!!!!!

2KCIO3= 2KCI+3O2

Using the equation above, if 25.6 g of KClare produced, then how many grams of
KCIO3 were consumed? (Type the numerical answer only, no words or label. Use
correct significant figures)

Answers

Answer:

The key to chemistry is to change everything to moles. Then when you have the answer in moles change the answer back to grams, liters, or whatever you want.

change 25 grams of potassium chlorate to moles.

calculate the gram molecular mass of potassium chlorate.

Chlorate is Cl with 3 oxygens. ate = saturated. Chlorine has seven valance electrons when it is saturated six of these electrons are used by oxygen ( 2 electrons per oxygen) leaving only 1 electron.

1 K x 39 grams/mole

+1 Cl x 35.4 grams/ mole

+3 O x 16 grams/ mole

= 122.4 grams / mole Potassium Chlorate

25

122.4

= moles.

2.05 moles of Potassium Chlorate.

There is a 1:1 mole ratio. 1 mole of Potassium Chlorate will produce 1 mole of Potassium Chloride.

2.05 moles of Potassium Chlorate will produce 2.05 moles of Potassium Chloride.

Find the gram molecular mass of Potassium Chloride.

1 K x 39 = 39

+1 Cl x 35.4 = 35.4

= 74.4 grams / mole.

2.05 moles x 74.4 grams/ mole = 15.2 grams

Explanation:

hope this helped :)

How much heat, in Joules, is needed to raise the temperature of 150 g of manganese by 22°C? (cmanganese = 0.477 J/g°C)

Answers

Answer:

1574joules of heat

Explanation:

Q= mc( T2-T1)

=150 * 0.477 *22

=1574 joules

1574.1 Joules heat is needed to raise the temperature of 150 g of manganese by 22°C.

Specific Heat

The quantity or amount of heat per unit mass required to raise the temperature of a body by one degree Celsius is known as specific heat. The unit of specific heat are joules or calories per gram per degree Celsius. Specific heat is an intensive property.

Calculate heat to raise temperature

Relationship between temperature and heat is expressed as:

Q = mcΔT

where,

Q is heat energy in Joules (J)

m is mass (in grams)

c is specific heat in J/g°C

ΔT is change in temperature

Now, put the values in above formula, we get that

Q = 150 × 0.477 × 22

Q = 150 × 10.494

Q = 1574.1 Joules

Thus, we can say that 1574.1 Joules is needed to raise the temperature  of 150g of manganese by 22°C.

Learn more about the specific heat here: https://brainly.com/question/21406849

#SPJ2  

The data showed that recently the alligator population has decreased. How could the decrease in the alligator
population affect the other populations? Be sure to explain whether the gar population, the diving duck population, a
the crab population will change, and why.

Answers

Answer:

Since the alligator population decreased, this means there are less predators for the gar. Less predators for the gar mean the gar population will increase.  More gar also means more competition for the diving duck in terms of animals that eat crabs, and thus the diving duck population will also decrease.

Explanation:

Hope this helped <3

How do you convert from grabs to moles of a substance
1. Divide by the molar mass
2. Subtract the molar mass
3. Add the molar mass
4. Multiple by the molar mass
PLEASE HELP !!!

Answers

The correct question is as follows:

How do you convert from grams to moles of a substance

1. Divide by the molar mass

2. Subtract the molar mass

3. Add the molar mass

4. Multiple by the molar mass

Answer: In order to convert from grams to moles of a substance divide by the molar mass.

Explanation:

The number of moles of a substance is the mass of substance in grams divided by its molar mass.

The formula to calculate moles is as follows.

[tex]Moles = \frac{mass}{molar mass}[/tex]

This means that grams are converted to moles when grams is divided by molar mass.

Thus, we can conclude that in order to convert from grams to moles of a substance divide by the molar mass.

10 points. Please help.


A balloon can hold 10 liters of a gas. If you blow up this balloon with 2 moles of oxygen gas at a pressure of 0.76 atmospheres, what is the temperature of the balloon? Pay attention to the unit of pressure used.

Answers

Answer:

The temperature of the balloon is 46.34 K.

Explanation:

An ideal gas is a theoretical gas that is considered to be composed of point particles that move randomly and do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.

An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of the gases:

P * V = n * R * T

In this case:

P= 0.76 atmV= 10 Ln= 2 molesR= 0.082 [tex]\frac{atm*L}{mol*K}[/tex]T= ?

Replacing:

0.76 atm* 10 L= 2 moles* 0.082 [tex]\frac{atm*L}{mol*K}[/tex] *T

Solving:

[tex]T=\frac{0.76 atm* 10 L}{2 moles* 0.082\frac{atm*L}{mol*K}}[/tex]

T= 46.34 K

The temperature of the balloon is 46.34 K.

What is the time it takes for half of the radioactive atoms in a sample of a radioactive element to decay?
A relative age
B. potassium-argon date
C. absolute age
D half-life

Answers

C. is the answer hope I helped have a good day

Answer:

D. Half-life

Explanation:

Half‐life is the amount of time it takes for approximately half of the radioactive atoms in a sample to decay into a more stable form. Every radioactive element has a different half‐ life.

What do you think of timothee chalamet statistics vid

Answers

Answer: EH, It was okay.

Explanation:

Answer:

It was so creative to finish up a statistics project with a statistics song- remarkable✌

Explanation:

Can someone please help me! I really need to do this so I can pass this class it’s the only assignment I haven’t done!!

Answers

Answer:

1. 868.8832g

2. .0053385mol

3.34.87 mol

4. 7049.088 g

Explanation:

I used the molar mass equation M= gram/mol and plugged in the numbers for each equation to figure out the missing part.

Which two geographic features form as a result of continental-continetal convergent
plates?

Answers

Answer:

Deep ocean trenches, volcanoes, island arcs, submarine mountain ranges, and fault lines are examples of features that can form along plate tectonic boundaries. Volcanoes are one kind of feature that forms along convergent plate boundaries, where two tectonic plates collide and one moves beneath the other.

Explanation:

I hope it's help u

Please brainiest

A 0.530 M Ca(OH)2 solution was prepared by dissolving 36.0 grams of Ca(OH)2 in enough water. What is the total volume of the solution thus formed?

Answers

Answer:

0.917

Explanation:

Answer:

0.917

Explanation:

Just took the test

Explain the reason that the atomic emission spectrum of hydrogen contains only four lines.
A)
The hydrogen atoms form a continuous series of quantized energy levels
that transmute at a variety of frequencies.
B)
Hydrogen atoms contain a limited number of quantized energy levels that
emit radiation at a limited number of frequencies.
C)
Many hydrogen atoms accomodate an array of quantized energy levels that
can release energy at a progression of frequencies.
A hydrogen atom consists of a sequence of quantized energy levels that
incorporate radiation only from consecutive frequencies.
D)

Answers

Answer:

Though a hydrogen atom has only one electron, it contains a large number of shells, so when this single electron jumps from one shell to another, a photon is emitted, and the energy difference of the shells causes different wavelengths to be released... hence, mono-electronic hydrogen has many spectral lines.

Explanation:

thank me later

The reason that the atomic emission spectrum of hydrogen contains only four lines is the hydrogen atoms form a continuous series of quantized energy levels that transmute at a variety of frequencies.

What is atomic emission spectrum of hydrogen?

The emission spectrum of hydrogen consist of numerous spectral series, the wavelength is postulated by Rydberg formula.

The reason behind the lines of spectrum is the transition of electron between two energies.

Thus, the correct option is A.

Learn more about atomic emission

https://brainly.com/question/11289486


#SPJ2

Which describes a possible path a carbon atom could take through the carbon cycle?
O A. Decomposers make coal into carbon. Carbon is released into the atmosphere. Plants take in carbon. Plant matter forms coal.
O B. Plants containing carbon die. Decomposers break down plant matter. Plant matter forms coal. Humans burn coal that releases
carbon into the atmosphere.
OC. Plant matter breaks down carbon in coal. Humans burn coal that releases carbon into the atmosphere. Decomposers break down
carbon in the atmosphere. Carbon in the atmosphere forms coal.
D. Humans burn coal that releases carbon into the atmosphere. Decomposers break down carbon in the atmosphere. Plant matter
breaks down carbon in the atmosphere. Plants containing carbon die.

Answers

Answer:

I know for a fact the correct answer is B

Answer:

A

Explanation:

BECAUSE plants use carbon dioxide for photosynthesis.

A gas has a volume of 4 liters at 50 oC. What will its volume be (in liters) at 100oC

Answers

Answer:

The volume of the gas at 100°C is 4.6189 liters.

Explanation:

For this problem we are going to use Charles' law. Charles' law states that the volume is directly proportional to temperature given that the pressure is constant. In order to use the equation, the unit of temperature should be in Kelvin.

The working equation is:

=

where V1 and T1 are the initial volume and temperature while V2 and T2 are the final conditions.

Let us convert first the temperatures before solving for the final volume.

To convert Celsius to Kelvin just add 273.15 to temperature in Celsius.

50°C + 273.15 = 323.15 K

100°C + 273.15 = 373.15 K

Solving for the final volume:

V₂ =

V₂ =

V₂ = 4.6189 L

Therefore the final volume of the gas at 100°C is 4.6189 L.

Explanation:

How many moles are in 7.36 x 1025 molecules of H2O?

Answers

Answer:

There are 122.1982401 moles of  H2O in [tex]7.36*10^{25}[/tex]  molecules of H2O

Explanation:

We know,

[tex]6.023*10^{23}[/tex]  molecules of H2O contains 1 mole H2O

            1      molecules of H2O contains [tex]\frac{1}{6.023*10^{23}}[/tex]  mole H2O

∴ [tex]7.36*10^{25}[/tex] molecules of H2O contains [tex]\frac{1}{6.023*10^{23}}*(7.36*10^{25})[/tex] moles of H2O

                                                               = 122.1982401 moles of  H2O

∴ There are 122.1982401 moles of  H2O in [tex]7.36*10^{25}[/tex]  molecules of H2O

please help me! I gave max brainly points!

Answers

Answer: C

Explanation:

Yes the answer is option C

A balloon that can hold 85 L of air is inflated with 7.056 grams of H2 gas at a pressure of 101.3 kPa. What is the temperature, in Celsius, of the balloon.

Answers

Answer:

Temperature is 258.32°C

Explanation:

Using the ideal gas equation;

PV = nRT        --------------(i)

Where;

P = Pressure of the gas

V = Volume of the gas

n = number of moles of the gas

R = Gas constant = 8.31 J/mol · K

T = Temperature

Given:

mass of H₂ gas = 7.056 grams

Volume of the gas = 85L = 8.5 x 10⁻³m³

Pressure of the gas = 101.3kPa = 101.3 x 10³Pa = 1.013 x 10⁵Pa

Steps:

(i) Using the mass of the gas, calculate the number of moles using the relation:

n = m / M         ----------------- (ii)

Where;

m = mass of H₂ = 7.056g

M = Molar mass of H₂ = 1g/mol

Substitute these values into equation (ii) as follows:

n = 7.056g / (1g/mol)

n = 7.056mol

(ii) Now calculate the temperature of the balloon by substituting the necessary values into equation (i)

(1.013 x 10⁵Pa)(8.5 x 10⁻³m³) = (7.056mol) (8.31 J/mol · K)(T)

T = (1.013 x 10⁵Pa)(8.5 x 10⁻³m³) ÷ (7.056mol) (8.31 J/mol · K)

Solving the above gives

T = 14.68K

Convert this to Celsius

T = 273 - 14.68

T = 258.32°C

Explain the reason that the atomic emission spectrum of hydrogen contains only four lines.

Answers

Answer:

Though a hydrogen atom has only one electron, it contains a large number of shells, so when this single electron jumps from one shell to another, a photon is emitted, and the energy difference of the shells causes different wavelengths to be released... hence, mono-electronic hydrogen has many spectral lines.

Explanation:

thank me later

The body system that transports molecules to and from all cells of the body

Answers

cardiovascular system

Answer:

El sistema cardiovascular tiene como función distribuir los nutrientes y el oxígeno a las células del cuerpo y recoger los desechos metabólicos para después eliminarlos en los riñones a través de la orina, y por el aire exhalado en los pulmones. El sistema cardiovascular comprende el corazón, que actúa como una bomba que mantiene el conjunto en funcionamiento, los vasos sanguíneos (arterias, venas y capilares), que son los conductos que transportan la sangre y, la sangre, que es el líquido fluido que contiene las células producidas por la maduración de las células madre de la médula

Write a hypothesis using IF-THEN - BECAUSE of statement.
Ahmed is curious about the death of the fishes in the ocean. He knows from his environmental chemistry class that pollutants like heavy metals can cause the rapid death of marine organisms. So, Ahmed did an experiment and obtained water samples. He tested that water contains a high amount of lead and chromium.

Answers

Answer:

The correct hypothesis would be - "if a water body contains a high amount of heavy metals such as chromium and lead then the death of the fishes will increase because lead and chromium affect the aquatic environment and gills of fishes."

Explanation:

Heavy metal like chromium in a high concentration can affect the gills of the fishes, it is seen in fishes that swim at the point of disposal of metals at thewater surface harm their gills. In high concentration, it becomes toxic for the fishes.

Lead also causes a negative impact on the aquatic ecosystem if accumulated in a high amount in the aquatic environment that leads to the death of the fishes.

Which of the following processes
release energy?
A. Water evaporating
B. Ice melting
C. steam condensing
D. wax melting

Answers

I believe it’s A not sure though

Which component of a river system is made of streams and small rivers that feed into a large river? Which component of a river system is also called a drainage basin? Which component of a river system is a ridge between water flowing in two directions?

Answers

Explanation: A river drainage basin is an area drained by a river and all of its tributaries. A river basin is made up of many different watersheds. A watershed is a small version of a river basin. Every stream and tributary has its own watershed, which drains to a larger stream or wetland.

The component of a river system is made of stream and small rivers that feed into a large river is tributaries. The component of a river system also called a drainage system is watersheds. The component of a river system is a ridge between water flowing in two directions is divided.

What are tributaries and watersheds?

Tributaries are the small rivers or streams that are made from the big or main river.

Watershed is the place where the rainwater from all river lines come to a point.

Thus, the correct options are tributaries, watersheds, and divided.

Learn more about tributaries and watersheds

https://brainly.com/question/1040502

#SPJ2

Other Questions
An escalator lifts people to the second floor of a building, 30 above the first floor. The escalator rises at a 30 angle. To the nearest foot, how far does a person travel from the bottom to the top of the escalator? What is the degree of the polynomial below?7x^5+6x^3+ 4x + 2A. 0B. 3C. 1D. 5 Here is ANOTHER ACCOUNT! DO NOT CLICK ON LINKS LIKE THESE! THEY ARE NOT SAFE! SPREAD THE WORD! what is the value of x?? When electrons flow through wires from a terminal to a terminal a/an _____created Missing measure help What is the healthy percentage of body fat for women?O 23-30%O 5-10%010-20%O 30-40%Question 21 pts What the correct answer era or fue 11Select the correct answer.Which statement best defines an inference? .a conclusion based on evidence and outside knowledgeO.B.the details stated directly by the author of a passageO c.a guess that relies only on the reader's prior experiencesD.the background information about a literary work WHATS THE AREA PLSSSSS .Which event sparked the protest movement known as the Arab Spring?Free speech was declared illegal in Iran.Ayatollah Khomeini became the ruler of Iran.A young man tragically killed himself in Tunisia.The six states of the Arabian peninsula united. write the chemical formula of 25 compound Suppose the price of a BMW falls. Explain the law of demand based on the income and substitution effects. please help now i need this quick PLEASE HELP QUICK.HELP. PLEASE EXPLAIN HOW TO FIND ANSWER ASWELL This fossil bird and this living salamander both have tails. However, they have different tail structures. The bird has a very short tail made of just one bone that helps it have a light skeleton for flying. The salamander has a long tail with many bones that helps it balance while it runs. What most likely explains why both the bird and salamander have tails and why the tails are different 23A university administered a survey to all incoming students regarding living arrangements for the upcoming school year. The results of the survey are displayed in the following two-way relative frequency table.University Living ArrangementsOn-Campus Off-Campus TotalFreshmen 0.44 0.28 0.72Transfer Students 0.21 0.07 0.28Total 0.65 0.35 1What percentage of incoming freshmen plan to live on-campus?A. 61.11%B. 67.69%C. 56%D. 44% Expand to write an equivalent expression. 5(7m2) One-fifth of the population, rank ordered by income, is A) An income quintile B) A population quintile. C) An earnings-population quintile. D) None of the choices are correct. An amoeba is only made up of one cell. This means that the amoeba is...A. multicellularB. unicellular