What is the temperature of an 11.2-L sample of carbon monoxide, CO, at 744 torr if it occupies 13.3 L at 55 °C and 744 torr? 3C The pressure is not changing, so it looks like a case where charles’ law can be use.

Answers

Answer 1

Answer: The tempearture of 11.2 L of CO is [tex]3.0^0C[/tex].

Explanation:

To calculate the final volume of the system, we use the equation given by Charles' Law. This law states that volume of the gas is directly proportional to the temperature of the gas at constant pressure.

Mathematically,

[tex]\frac{V_1}{T_1}=\frac{V_2}{T_2}[/tex]

where,

[tex]V_1\text{ and }T_1[/tex] are the initial volume and temperature of the gas.

are the final volume and temperature of the gas.

We are given:

[tex]V_1=11.2L\\T_1=?\\V_2=13.3L\\T_2=55^0C=(55+273)K=328K[/tex]

Putting values in above equation, we get:

[tex]\frac{11.2L}{T_1}=\frac{13.3L}{328K}\\\\T_1=276K=(276-273)^0C=3.0^0C[/tex]

Thus the tempearture of 11.2 L of CO is [tex]3.0^0C[/tex], pressure remaining constant.


Related Questions

Question 10
Which of the following fuels is most likely to perform poorly in cold climates?
A. Petrol
B. Petrodiesel
C. Biodiesel made from plant oil.
D. Biodiesel made from animal fat.

Answers

Answer:

C. Biodiesel made from plant oil.

Explanation:

The  type of vegetable oil used in production greatly affects the performance of biodiesel in the winter. The less saturated the fat, the better the performance in winter time. Canola oil works very well for low temperature biodiesel, and palm oil is among the worst for cold weather performance.

Hope this helped!!!

lave
Use the drop-down menus to identify the parts of a
wave.
A
B:
C
D

Answers

this doesn’t make sense

Answer:

Use the drop-down menus to make your selections.

What is the difference between wave A and wave B?

✔ Wave A has higher amplitude than wave B.

What is the difference between wave C and wave D?

✔ Wave C has a lower frequency than wave D.

Explanation:

When 148. mg of a certain molecular compound X are dissolved in 75.g of cyclohexane (CH), the freezing point of the solution is measured to be 59 'C. Calculate the molar mass of X If you need any additional information on cyclohexane, use only what you find in the ALEKS Data resource. Also, be sure your answer has a unit symbol, and is rounded to l significant digit. XS ?

Answers

Answer: The molar mass of X is 61.3g/mol

Explanation:

Depression in freezing point is given by:

[tex]\Delta T_f=K_f\times m[/tex]

[tex]\Delta T_f=T_f^0-T_f=(6.55^0C-5.9^0C)=0.65^0C[/tex] = Depression in freezing point

[tex]K_f[/tex] = freezing point constant = [tex]20.2^0C/mol[/tex]

m= molality  = [tex]\frac{\text{Mass of solute}}{\text{Molar mass of solute}\times \text{Mass of solvent in Kg}}[/tex]

where,  

Now put all the given values in this formula, we get

[tex]0.65^0C=20.2°C/m\times frac{0.148g}}{M\times 0.075kg}[/tex]

[tex]M=61.3g/mol[/tex]

Thus molar mass of X is 61.3g/mol

how we can remove temporary hardness of water?and write the chemical reaction?​

Answers

Answer:

it can be removed

1. by boiling

Ca(HCO3)2 > CaCO3 + H2O +CO2

2. by treating with calcium hydroxide

Calculate the value of the equilibrium constant for the following system, where the concentrations of reactants and products are: [NO]=1.2x10^-3M , [NO2]=1.5x10-^1M , [N2O]=2.4x10^-3M

Answers

Answer:

The equilibrium constant is 2.08x10⁵

Explanation:

Based on the reaction:

3NO ⇄ N₂O + NO₂

The equilibrium constant, k, is defined as:

k = [NO₂] [N₂O] / [NO]³

Where the [] is the molarity in equilibrium of each specie.

Computing te values of the problem:

k = [1.5x10⁻¹M] [2.4x10⁻³M] / [1.2x10⁻³M]³

k = 2.08x10⁵

The equilibrium constant is 2.08x10⁵

Use the equation qliquid = m × c × ΔT to calculate the heat gained by the cold liquid. Use the specific heat for the liquid you selected.

Use the equation qwater = m × c × ΔT to calculate the heat lost by the hot water. Show your work using the problem-solving method shown in previous rubrics.

Answers

Complete question :

Use the equation qliquid = m × c × ΔT to calculate the heat gained by the cold liquid. Use the specific heat for the liquid you selected.

m = 248.9 g ; T = 72.6°C ; C = 3.73 j/g°C

Use the equation qwater = m × c × ΔT to calculate the heat lost by the hot water. Show your work using the problem-solving method shown in previous rubrics.

M = 237 g ; T = 41.2°C ; C = 4.184 j/g°C

Answer:

Quantity of heat gained = 67401.6 Joules

Quantity of heat lost by hot water = 40854.25 Joules

Explanation:

The heat gained by cold liquid :

Q = m × c × ΔT

m = 248.9 g ; T = 72.6°C ; C = 3.73 j/g°C

Q = 248.9 * 3.73 * 72.6

Q = 67401.6 Joules

Quantity of heat gained = 67401.6 Joules

Heat lost by hot water :

m × c × ΔT

M = 237 g ; T = 41.2°C ; C = 4.184 j/g°C

Q = 237 * 41.2 * 4.184

Q = 40854.25 Joules

Quantity of heat lost by hot water = 40854.25 Joules

Collisions app covalent bonding level 15

Answers

Answer: change the nitrogen with oxygen for the first part then have the nitrogens collided instead of oxygens in the last part - not sure if my terminology is correct but here is the pic to show!

Explanation:

Identify the term that matches each definition.

a. A characteristic that describes substances that evaporate readily, producing large amounts of vapors _________
b. The front vent of a fume hood, which helps maintain proper air circulation ___________
c. The glass panel in front of the fume hood that shields the user from fumes and other hazards ___________
d. The horizontal, flat area of a fume hood upon which experiments are carried out ________

Answers

Answer:

a. Volatile.

b. Air foil.

c. Sash.

d. Work surface.

Explanation:

In science, matter can be defined as anything that has mass and occupies space. Any physical object that is found on earth is typically composed of matter. Matter are known to be made up of atoms and as a result has the property of existing in states.

Generally, matter exists in three (3) distinct or classical phases and these are;

I. Solid.

II. Liquid.

III. Gas.

Matching the terms with their respective definition, we have;

a. Volatile: A characteristic that describes substances that evaporate readily, producing large amounts of vapors.

b. Air foil: the front vent of a fume hood, which helps maintain proper air circulation.

c. Sash: the glass panel in front of the fume hood that shields the user from fumes and other hazards.

d. Work surface: the horizontal, flat area of a fume hood upon which experiments are carried out.

Calculate the Standard Enthalpy of the reaction below:
NH3(g) + HCl (g) → NH4Cl(s)
Using the following Enthalpy of Reactions:
2HCl(g) → H2(g) + Cl2(g)
AH = +184.6 kJ
2H2(g) + 12 N2(g) + 2 Cl2(g) NH4Cl(s) AH = -314.4 kJ
N2(g) + 3 H2(g) → 2 NH3(g)
AH = +184.6 kJ​

Answers

Answer:

(we use hess's law) it is so simple but the second reaction is not correct please right it

A 1.4639-g sample of limestone is analyzed for Fe, Ca, and Mg. The iron is determined as Fe2O3 yielding 0.0357 g. Calcium is isolated as CaSO4, yielding a precipitate of 1.4058 g, and Mg is isolated as 0.0672 g of Mg2P2O7. Report the amount of Fe, Ca, and Mg in the limestone sample as %w/w Fe2O3, %w/w CaO, and %w/w MgO

Answers

Answer:

A) w/w % of Fe - 2.44%

B) w/w % of Mg - 4.590%

C) w/w % of Ca - 96%

Explanation:

A) w/w % of Fe in limestone as Fe2O3 = (Mass of Fe2O3 /Mass of limestone) x 100

 0.0357/1.4639 X 100

= 2.438 =2.44

B) w/w % of Mg in limestone as Mg2P2O7 = (Mass of Mg2P2O7 /Mass of limestone) x 100

= 0.0672/1.4639 X 100

= 4.590

C) w/w % of Ca in limestone as CaSO4 = (Mass of CaSO4/Mass of limestone) x 100

= 1.4058/1.4639 X 100

= 96

                                                           

Answer:Fe =1.71%    Ma=0.99%    Ca=28.24%

Explanation:

How many grams of H2SO4 will react 650.0 grams of NaOH?

Answers

Answer:

H2SO4 + 2NAOH➡NA2SO4+2H2O

H2SO4 = 1*2 +32+16*3= 98g

NAOH = (11+16+1)=28

Explanation:

To calculate the number of Mole = Mole *Molar Mass

To calculate for gram = Mole/ Molar Mass

20.5g NaoH/1 * 1 mole NaOH/28g NaoH = 0.73M NaoH

0.73M NaoH /1 * 1 M H2SO4 /2M NaoH = 0.37M H2SO4

0.37 M H2SO4 /1 * 98g H2SO4 /1M H2SO4 = 0.00367g H2SO4

:- 0.00367g of Sulphuric Acid will be needed to complete the reaction.

In the western U.S., ranchers aggressively killed wolves because they posed a threat to their cattle. As the wolf population declined, the deer population began increasing. As a result, the surrounding forest ecosystems experienced increasing damage. The large number of deer ravaged vegetation and destroyed young trees. The entire ecosystem became degraded until wolves became protected when they were determined to be an endangered species. Based on this information, what can you infer about the role of the wolves in this ecosystem? Please make it 3-5 sentences. Thank you so much

Answers

Answer:

Explanation:

You can make a couple of statements.

The wolves are preditors. They eat meat.The wolves hunt only 1 kind of food. They are not interested in young trees or grass (well not much anyway). If one species is allowed to get out of control, the entire ecosystem suffers because of it.This last statement only becomes true if man allows the hunted species that controlled the deer to regain good numbers. Man can be a blockhead sometimes; he learns slowly at times.

Answer:

The wolves role in the ecosystem is to hunt/eat deer. In the question it states, "...ranchers aggressively killed wolves because they posed a threat to their cattle. As the wolf population declined, the deer population began increasing." It's clearly cause and affect, the wolves use to eat a lot of deer, then a large percentage of wolves died by the ranchers. The wolves role in the ecosystem is to hunt deer and help balance out animal to vegetation ratio.

Explanation:

Because i'm awesome lol

(Give me good ratings pleaseeeee.

Calculate the pH when 64.0 mL of 0.150 M KOH is mixed with 20.0 mL of 0.300 M HBrO (Ka = 2.5 × 10⁻⁹)

Answers

Answer:

The answer is "12.06"

Explanation:

Given:

[tex]M(HBrO) = 0.3\ M\\\\V(HBrO) = 20 \ mL\\\\M(KOH) = 0.15 \ M\\\\V(KOH) = 64 \ mL[/tex]

[tex]\to mol(HBrO) = M(HBrO) \times V(HBrO) = 0.3 M \times 20 mL = 6 \ mmol\\\\\to mol(KOH) = M(KOH) \times V(KOH)= 0.15 M \times 64 mL = 9.6 mmol[/tex]

  6 mmol of both will react

excess KOH remaining[tex]= 3.15 \ mmol[/tex]

Volume[tex]= 20 + 64 = 84 \ mL[/tex]

[tex][OH^{-}] = \frac{ 9.6 \ mmol}{84\ mL} = 0.01142\ M[/tex]

use:

[tex]pOH = -\log [OH^-][/tex]

        [tex]= -\log (1.142\times 10^{-2})\\\\= 1.94[/tex]

use:

[tex]PH = 14 - pOH[/tex]

       [tex]= 14 - 1.94\\\\= 12.06[/tex]

The pH of the resulting  solution is  12.63.

The equation of the reaction is;

HBrO(aq) + KOH(aq) ------> KOBr(aq) + H2O(l)

Number of moles of KOH= 64/1000 × 0.150 M = 0.0096 moles

Number of moles of HBrO = 20/1000 × 0.300 M = 0.0060 moles

Number of moles of excess base = 0.0096 moles -  0.0060 moles = 0.0036 moles

Total volume of solution = 64.0 mL +  20.0 mL = 84 mL = 0.084 L

Molarity of excess base =  0.0036 moles/0.084 L = 0.043 M

pOH = -log[OH-]

pOH = -log[ 0.043 M]

pOH = 1.37

pH + pOH = 14

pH = 14 -pOH

pH = 14 - 1.37

pH = 12.63

Learn more: https://brainly.com/question/11897796

Draw curved arrows to show electron reorganization for the mechanism step below. (For a resonance-stabilized anion, draw a single resonance form with the negative charge on oxygen, not on carbon.) Make the ends of your arrows specify the origin and destination of reorganizing electrons.

Answers

Answer:

Explanation:

Dear student, this question appears to be incomplete but in the diagram attached below, I have carefully drawn out the required organic structure.

The aim of this question is to show the mechanism of the given structure and to point out the resonance structure.

The first diagram shows the complete part (i.e. the structure of the organic compound) and its major product(answer).

The second diagram shows the mechanism by which we arrived at the major product.

From the second diagram attached below, the -oxo substituent of the methanol attacks the hydrogen atom as shown below, leading to the formation of the enolate ion (a resonance stabilized anion).

However, this is because the alpha carbon attaches to the hydrogens readily leaves as H⁺ to yield an enolate ion as a result of -C- that is doubly bonded to oxygen (an Electron withdrawing group).

Kindly check out the images attached below to see the mechanism.

The different unit cell types have a different packing efficiency. The simple cubic has the least efficient packing and the face-centered cubic has the most efficient packing (sometimes the face-centered cubic is called cubic closest packing). You can determine what percent of the unit cell is occupied by (1) determining the volume of the whole unit cell and (2) determining the volume of the occupied space by the atoms in the unit cell. Remember that the volume of a cube is V

Answers

Answer:

The answer is "52.8".

Explanation:

Please find the graph file in the attachment.

They have the atoms in 8 corners with one unit cell in an one so mesh (SCC).

Atoms throughout the corner contribute [tex]\frac{1}{8}[/tex]to both the cell unit

Atom number per SCC unit cell, [tex]Z = (8 \times \frac{1}{8}) = 1[/tex]

Let 'r' become the atom's radius.  [tex]r = 3.43\times 10^{-8}\ \ cm[/tex]

We can see from the diagram that edge length [tex]AB = a = 2r[/tex]

[tex]Packing\ efficiency = \frac{(1 \ atom \ Volume \times Z)}{Volume \ of \ unit\ cell \times 100}\\\\[/tex]

                                 [tex]= \frac{\frac{4}{3}\times \pi \times r^3 \times 1}{a^3 \times 100}\\\\=\frac{\frac{4}{3}\times \pi \times r^3 \times 1}{(2r)^3 \times 100} \\\\=\frac{\frac{4}{3}\times \pi \times( 3.43\times 10^{-8}cm)^3 \times 1}{(2\times 3.43\times 10^{-8}cm)^3 \times 100}\\\\= 52.8 \%[/tex]

How many moles of BaS would be used to make 1200 mL of a 10.OM solution?

Answers

200 bas would be used to make 1200 ml of soulution

Which of the solids in the following set should you test to investigate for the effects of ANIONS on pH? Will give brainliest
-KClO
-RbF
-AlBr3
-Rb2SO3
-CrCl3

Answers

Answer:

KCIO

Explanation:

the only reason is because I looked online and the meaning for that is potassium hypochlorite my guy so if this is not right then I'm sorry but good luck.

You and your science group have been handed five mineral samples to identity. First, you on the minerals by color None of the
minerals are white. You and your group know that you probably do not have

A) Calcite

B) gypsum

C) Calcite and Talc

D) feldspar and calcite

Answers

Answer: A

Explanation:

calcite for sure, but feldspar is also white so it could be d.

help asap please, What does Newton's law of gravitation state that two masses will do?


always fall


not have any affect on each other


attract each other


repel each other

Answers

Answer:

According to Newton's law of gravitation two objects attract each other

Answer: C. Attract each other!

Explanation:

PLZ HELP ME ASAP!!!!(I WILL ALSO MARK BRAINLIEST!!!)
(True or False) A cold front often signals sunny warm weather.

Answers

False

The cold front shoves the warmer air ahead of it upward, and as it cools the air discharges its moisture. The upheaval of warm air and the development of cumulonimbus clouds signals thunderstorms with heavy rains, and some strong cells capable of producing heavy downpours.
your answer is False!!! (So u can give that person a brainliest

A 15.0 mL solution of 0.10 M Fe(NO3)3 reacts with K2C204 ​according to the reaction 2 Fe(NO3)3 + 3 K2C2O4 → Fe2 (C2O4)3 ​+ 6 KNO3 . What volume of 0.30 M K2C2O4 is needed to react completely?

Answers

The volume of 0.30 M potassium chromate needed to react with 15 ml of 0.10 M ferric nitrate is 5 ml.

What is molarity?

Molarity of a solution is the ratio of its number of moles of solute to the volume of solution in liter. It is the common term used to express the concentration of a solution.

Let V1 and M1 be the volume and molarity of solution 1 and V2 and M2 that of solution 2 which are reacting together.

Thus, V1 M1 = V2 M2.

The volume of 0.30 M potassium chromate is calculated as  follows:

volume = (15 ml × 0.10 M) / 0.30 M = 5 ml.

Therefore, the volume of the potassium chromate solution is 5 mL.

To find more on molarity, refer here:

https://brainly.com/question/8732513

#SPJ1

For the wild type (unmutated) enzyme, you measure a rate of p-nitrophenol release by the change in absorbance at 405 nm (for the slower phase only) of 0.216 (in a cuvette with a pathlength of 1 cm) over the course of two minutes. Use the Beer-Lambert Law to calculate the concentration of product released over this time; the extinction coefficient of p-nitrophenol at 405 nm is 18,000 M-1 cm-1.

Answers

Answer:

1.2x10⁻⁵M = Concentration of the product released

Explanation:

Lambert-Beer's law states the absorbance of a solution is directly proportional to its concentration. The equation is:

A = E*b*C

Where A is the absotbance of the solution: 0.216

E is the extinction coefficient = 18000M⁻¹cm⁻¹

b is patelength = 1cm

C is concentration of the solution

Replacing:

0.216 = 18000M⁻¹cm⁻¹*1cm*C

1.2x10⁻⁵M = Concentration of the product released

calculate the percentage of CL in AL(CLO3)3​

Answers

Answer:

38.4%

Explanation:

We'll begin by calculating the molar mass of Al(ClO₃)₃. This can be obtained as follow:

Molar mass of Al(ClO₃)₃

= 27 + 3[35.5 + (16×3)]

= 27 + 3[35.5 + 48]

= 27 + 3[83.5]

= 27 + 250.5

= 277.5 g/mol

Next, we shall determine the mass of Cl in Al(ClO₃)₃. This can be obtained as follow:

Mass of Cl in Al(ClO₃)₃ = 3 × Cl

= 3 × 35.5

= 106.5 g

Finally, we shall determine the percentage of Cl in Al(ClO₃)₃. This can be obtained as follow:

Mass of Cl in Al(ClO₃)₃ = 106.5 g

Mass of Al(ClO₃)₃ = 277.5 g

Percentage of Cl =?

Percentage of Cl = mass of Cl / mass of Al(ClO₃)₃ × 100

Percentage of Cl = 106.5 / 277.5 × 100

Percentage of Cl = 38.4%

Can you all go vote for Dacia Campbell for Brainly Educator of The Year!!!!!
It would mean a ton!!! Plus, I'll give your profile a big THANK YOU...I'll give Brainliest and you get 50 points! Please, please, please. Go vote for her!

Answers

Answer:

i voted her!!!!

Explanation:

heat would best be transferred by conduction between
A. a candle and the air
B. an oven and a glass dish
C. a stove and a copper pot
D. water and a wooden spoon

Answers

Stove and copper pot. The candle and air transfer heat through convection, the oven cannot properly conduct heat to the glass dish, wooden spoon is a horrible conductor in any form, and the copper pot is metal so it can better conduct with the stove

Answer:

C. or B.

Explanation:

The reason I chose c best, is when your cooking something with a pot with food in it max heat in about 5 minutes, the handle starts to get warmer every minute. This is conduction, where the heat transfers from the very bottom all the way to the very edge of something that is heated at a certain temperature.

the solubility of PbSO4 is 0.048g/Liter. what is the Ksp of PbSO4? (MMPbSO4 = 303.3)​

Answers

Answer:

Ksp of PbSO4 is 2.5 *10^-8

Explanation:

Given -

Solubility of PbSO4 = 0.048g/Liter

[Pb+2] * [SO42-] = mass/molecular weight of PbSO4

[Pb+2] * [SO42-] =  0.048g/Liter/303.3g/mol = 0.000158 M

Concentration of PbSO4 = moles/volume = 0.000158 M/1L = 0.000158 M

Ksp = [Pb+2] * [SO42-]

ksp = 0.000158 * 0.000158 = 2.5 *10^-8

Select the statement that is FLASE about this experiment. Group of answer choices Changing temperature will affect the redox potential. Changing concentration will affect the redox potential. Changing metal solution will affect the redox potential. To ensure stable reading, insert the conductivity meter in the solution for at least 60 seconds. To ensure consistent data, collect the redox potential values at least three times.

Answers

Answer:

To ensure stable reading, insert the conductivity meter in the solution for at least 60 seconds.

Explanation:

The False statement is ; To ensure stable reading, insert the conductivity meter in the solution for at least 60 seconds.

All other statement will affect the experiment's redox potential but  inserting the conductivity meter in the solution for at least 60 seconds will not affect the Redox potential  .

Redox potential is used to describe/measure a system's oxidizing capacity

PLEASE HELP ITS DUE SOON AND I DONT UNDERSTAND
How many grams of KClO3 must be decomposed to produce 3.45 L of oxygen at STP with a 75.3% yield? 2 KClO3(s) à 2 KCl(s) + 3 O2(g)

Answers

the answer is 137 grams boyyy

Acid-catalyzed addition of water to an alkene yields an alcohol with Markovnikov regiochemistry.

a. True
b. False

Answers

Answer:

True

Explanation:

Markovnikov rule states that the negative part of the addendum is added to the carbon atom having the least number of hydrogen atoms.

This means that during acid-catalyzed addition of water to an alkene, the -OH is added to the more substituted carbon atom while the -H is added to the least substituted carbon atom in obedience to Markovnikov regiochemistry.

Answer:

a. True

Explanation:

Acid-catalyzed addition of water to an alkene yields an alcohol with Markovnikov regiochemistry. The electrophilic H+ adds to the sp2 carbon with the most hydrogens to yield the most stable carbocation intermediate, which then adds water to give the product alcohol.

3. Convert the word equations below to symbolic:
Sodium + chlorine sodium chloride
• Calcium + bromine ---- calcium bromide
• Potassium + water → potassium hydroxide + hydrogen
ot

Answers

Answer:

1)2Na + Cl2 ----> 2NaCl

2)Ca + Br2 ---->CaBr2

3)K + H2O -----> KOH + H2

Other Questions
1. interpret data- based on the data, describe what alicia did.2. draw conclusions- what conclusions can you draw? what does stirring do in terms of heat transfer?help :( define the following negotiation styles competing Find the midpoint of the segment with the following endpoints (7-6) and (4-10) The sum of two numbers is 56. One number is 3 times as large as the other. What are the numbers?larger numbersmaller number Take notes on the similarities and differences and prepare to write a 250-300 word essay comparing and contrasting two aspects of Gupta society and our society today. Consider g(x) = 3x 3. What is an equation for each graph in terms of g?7. y-intercept is 08. y-intercept is 89. y-intercept is 3 Question 95 ptsWhich energy transfer is correctly matched?Fusion in the sun: chemical to light and heatLighting a match: heat energy into chemical energya cell phone: thermal to electricalTurning on a ceiling fan: electrical to mechanical Simplify: 6^6/6^3 Leave your answer in exponential form How many inches is in 5 1/4 feet What is syntax?A an authors word choiceB an authors sentence structure C time and diction togetherD formal language in poetry balana camereialim fois apresenta superzonitqueque, em detinterminadsComincialimparts Catsde Why does White Fang look forward to the fights Beauty arranges? No links plz (d) You will live for 500 years.state whether the following event is certain, impossible, even,likely or unlikely What is the slope of the graph?plz help Jamal's car travels an average of 16.7 miles per gallon of gas.A full tank of gas is 20 gallons. Jamal has driven 292 milessince he last filled his gas tank. How many more miles canJamal expect to travel on this same tank of gas? The diameter of a circle is 4cm. Find it area to nearewt tenth. HELP PLEASE 10 POINTS AND BRAINLIEST Please help out!!!! :/// Indicate whether the given structure is located in the outer, middle, or inner ear. pharngotympanic tube helicotrema stapedius What is .66666666 as a fraction?