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ANEK [815]
3 years ago
12

One type of breathalyzer employs a fuel cell to measure the quantity of alcohol in the breath. When a suspect blows into the bre

athalyzer, ethyl alcohol is oxidized to acetic acid at the anode:
CH3CH2OH(g)+4OH−(aq)→HC2H3O2(g)+3H2O(l)+4e−

At the cathode, oxygen is reduced:
O2(g)+2H2O(l)+4e−→4OH−(aq)

The overall reaction is the oxidation of ethyl alcohol to acetic acid and water. When a suspected drunk driver blows 186 mL of his breath through this breathalyzer, the breathalyzer produces an average of 320 mA of current for 10 s.

Required:
Assuming a pressure of 1.0 atm and a temperature of 26C, what percent (by volume) of the driver's breath is ethanol?
Chemistry
1 answer:
Gekata [30.6K]3 years ago
3 0

Answer:

The percent of ethanol is 0.1093%

Explanation:

Given:

t = time = 10 s

I = current = 320 mA

F = Faraday's constant = 96485.3365 C mol⁻¹

n = number of electrons = 4

Molecular weight of ethanol = 46 g/mol

Question: What percent (by volume) of the driver's breath is ethanol, %E = ?

First, it is necessary to calculate the mass of ethanol:

W=\frac{\frac{46}{4} *0.32*10}{96485.3365} =3.814x10^{-4} g

The moles of ethanol:

n_{ethanol} =3.814x10^{-4} g*\frac{1mol}{46} =8.291x10^{-6} moles

Applying the equation of ideal gas:

V=\frac{nRT}{P}

Here:

T = 26°C = 299 K

P = 1 atm

Substituting values:

V=\frac{8.291x10^{-6}*0.082*299 }{1} =2.033x10^{-4} L=0.2033mL

The percent of ethanol:

E=\frac{0.2033}{186} *100=0.1093%

You might be interested in
In two or more complete sentences, develop a logical argument to either support or refute the following statement. Be sure to pr
Yuri [45]

We use logic every day to figure out test questions, plan our budgets, and decide who to date. We borrow from the vocabulary of logic when we say, "Brilliant deduction" or even "I don't want to argue about it." In the study of logic, however, each of these terms has a specific definition, and we must be clear on these if we are to communicate.

Vocabulary

Proposition --

T or F in an argument, but not alone. Can be a premise or conclusion. Is not equal to a sentence.

Premise --

Proposition used as evidence in an argument.

Conclusion --

Proposition used as a thesis in an argument.

Argument --

A group of propositions of which one is claimed to follow from the others.

Induction --

A process through which the premises provide some basis for the conclusion

Deduction --

A process through which the premises provide conclusive proof for the conclusion.

Argument Indicators: Premise Indicators: Conclusion Indicators:

should

must

ought  

necessarily

since  

because

for  

as

inasmuch as  

for the reason that

first ...

therefore

hence

thus

so

consequently  

it follows that  

one may infer

one may conclude

When dealing with persuasive writing, it will be helpful for you to outline the argument by premises and conclusions. By looking at the structure of the argument, it is easy to spot logical error.

Universities are full of knowledge. The freshmen bring a little in, and the seniors take none away, and knowledge accumulates.

-- Harvard President A. L. Lowell

Premise 1

Premise 2

Premise 3

Conclusion Freshmen bring a little (knowledge) in

Seniors take none away

Knowledge accumulates

Universities are full of knowledge

Example 2

(Here, the conclusion of one argument is used as a premise in another. This is very common.)

Even though there may be a deceiver of some sort, very powerful and very tricky, who bends all his efforts to keep me perpetually deceived, there can be no slightest doubt that I exist, since he deceives me; and let him deceive me as much as he will, he can never make me be nothing as long as I think I am something. Thus, after having thought well on this matter, and after examining all things with care, I must finally conclude and maintain that this proposition: I am, I exist, is necessarily true every time that I pronounce it or conceive it in my mind.

-- Rene Descartes, *Meditations*

Argument 1 Premise 1:

Conclusion of Argument 1

Argument 2 Premise 1:

Conclusion:

To be deceived ... I must exist

When I think that I exist I cannot be  

deceived about that

I am, I exist, is necessarily true ... .

Exercises

Find the Arguments and Outline them in These Statements:

1. Ask the same for me, for friends should have all things in common.

-- Plato, Phaedrus

2. Matter is activity, and therefore a body is where it acts; and because every particle of matter acts all over the universe, every body is everywhere.

-- Collingwood, The Idea of Nature

3. The citizen who so values his "independence" that he will not enroll in a political party is really forfeiting independence, because he abandons a share in decision©making at the primary level: the choice of the candidate.

-- Felknor, Dirty Politics

Reaching Logical Conclusions

This article is reprinted from pages 78-79 of Pearson-Allen: Modern Algebra , Book One. In the book it is one of several between-chapter articles that add interest and provike thought on subjects related to the topics discussed in the text.

Consider the two statements:

1. Any member of a varsity squad is excused from physical education.

2. Henry is a member of the varsity football squad.

Our common sense tells us that if we accept these two statement as true, then we must accept the following third statement as true:

3. Henry is excused from physical education.

We say that the third statement follows logically from the other two.

In drawing logical conclusions it does not matter whether the statements we accept as true are reasonable or sensible. This is because we depend entirely upon the form of the statements and not upon what we are talking about. Thus, if we accept the following statements as true:

1. All whales are mammals;  

2. All mammals are warm-blooded animals;  

3. All warm-blooded animals are subject to colds;

then we must conclude that


8 0
3 years ago
What would be the major product obtained from hydroboration–oxidation of the following alkenes?
zmey [24]

Answer:

a. 3-methylbutan-2-ol

b. 2-methylcyclohexan-1-ol

Explanation:

For this reaction, we must remember that the hydroboration is an <u>"anti-Markovnikov" reaction</u>. This means that the "OH" will be added at the <em>least substituted carbon of the double bond.</em>

In the case of <u>2-methyl-2-butene</u>, the double bond is between carbons 2 and 3. Carbon 2 has two bonds with two methyls and carbon 3 is attached to 1 carbon. Therefore <u>the "OH" will be added to carbon three</u> producing <u>3-methylbutan-2-ol</u>.

For 1-methylcyclohexene, the double bond is between carbons 1 and 2. Carbon 1 is attached to two carbons (carbons 6 and 7) and carbon 2 is attached to one carbon (carbon 3). Therefore<u> the "OH" will be added to carbon 2</u> producing <u>2-methylcyclohexan-1-ol</u>.

See figure 1

I hope it helps!

8 0
3 years ago
A student runs an experiment in the lab and then uses the data to prepare an Arrhenius plot of the natural log of the rate const
Thepotemich [5.8K]

Answer:

21.86582KJ

Explanation:

The graphical form of the Arrhenius equation is shown on the image attached. Remember that in the Arrhenius equation, we plot the rate constant against the inverse of temperature. The slope of this graph is the activation energy and its y intercept is the frequency factor.

Applying the equation if a straight line, y=mx +c, and comparing the given equation with the graphical form of the Arrhenius equation shown in the image attached, we obtain the activation energy of the reaction as shown.

5 0
3 years ago
Enter the appropriate symbol for an isotope of potassium-39 corresponding to the isotope notation A/Z x
Taya2010 [7]
Appropriate symbol for an isotope of potassium - 39 corresponding to the isotope notion r A ZX
7 0
3 years ago
A solution contains 0.036 M Cu2+ and 0.044 M Fe2+. A solution containing sulfide ions is added to selectively precipitate one of
Ratling [72]

Answer:

The precipitate is CuS.

Sulfide will precipitate at  [S2-]= 3.61*10^-35 M

Explanation:

<u>Step 1: </u>Data given

The solution contains 0.036 M Cu2+ and 0.044 M Fe2+

Ksp (CuS) = 1.3 × 10-36

Ksp (FeS) = 6.3 × 10-18

Step 2:  Calculate precipitate

CuS → Cu^2+ + S^2-         Ksp= 1.3*10^-36

FeS → Fe^2+ + S^2-      Ksp= 6.3*10^-18

Calculate the minimum of amount needed to form precipitates:

Q=Ksp

<u>For copper</u>  we have:  Ksp=[Cu2+]*[S2-]

Ksp (CuS) = 1.3*10^-36 = 0.036M *[S2-]

[S2-]= 3.61*10^-35 M

<u>For Iron</u>  we have: Ksp=[Fe2+]*[S2-]

Ksp(FeS) = 6.3*10^-18 = 0.044M*[S2-]

[S2-]= 1.43*10^-16 M

CuS will form precipitates before FeS., because only 3.61*10^-35 M Sulfur Ions are needed for CuS. For FeS we need 1.43*10^-16 M Sulfur Ions which is much larger.

The precipitate is CuS.

Sulfide will precipitate at  [S2-]= 3.61*10^-35 M

3 0
3 years ago
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