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14 days ago

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Use the tabulated values of ΔG∘f to calculate E∘cell for the fuel cell breathalyzer, which employs the reaction below. (ΔG∘f for

HC2H3O2(g)= -374.2 kJ/mol.) CH3CH2OH(g)+O2(g)→HC2H3O2(g)+H2O(g)

1 answer:

castortr0y [2.9K]14 days ago

7 0

0.97 V The relationship between ΔGºf and Eºcell is given by ΔGºf = -nFEºcell, where ΔGºf is the Gibbs Free energy change of formation at STP in Joules, n represents the number of moles of electrons, F is Faraday's constant (96,500 coulombs), and Eºcell indicates the emf of the cell under standard conditions. The redox reaction is CH3CH2OH(g) + 2H2O ⇒ HC2H3O2(g) + 4 H⁺ +4e⁻; O2 + 4 H⁺ + 4e⁻ ⇒ 2 H2O. Using the formula Eºcell = -ΔGºf /nF = -374.2 x 1000 J/(4x 96500 coulombs) gives 0.97 V.

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Which environmental factor could lead to a decrease in genetic variation in a population of tuna? A.an increase in food availabi

Alekssandra [2891]

Hello! Your inquiry seeks to identify the environmental factor resulting in diminished genetic diversity within a tuna population. The accurate response is B: An increase in pollution.

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11 days ago

Read 2 more answers

PART A: Use the following glycolytic reaction to answer the question. If the concentration of DHAP is 0.125 M and the concentrat

alisha [2865]

Answer:

For A: The change in free energy for the reaction is -5339.76 J/mol

For B: Free energy change is expressed in kJ/mol

For C: The forward reaction favors progression, while the reverse reaction does not.

Explanation:

Regarding the specified chemical reaction:

$DHAP\rightleftharpoons G_3P$

For A:

The relationship between standard Gibbs free energy and equilibrium constant is as follows:

$\Delta G^o=-RT\ln K_{eq}$

The free energy change can be calculated using the following equation:

$\Delta G=\Delta G^o+RT\ln Q$

Or,

$\Delta G=-RT^o\ln K_{eq}+RT\ln Q$

where,

$\Delta G$ = Change in free energy

R = Gas constant = $8.314J/K mol$

$T^o$ = standard temperature = $25^oC=[273+25]K=298K$

T = temperature of the cell = $37^oC=[273+37]K=310K$

$K_[eq}$ = equilibrium constant = $5.4\times 10^{-2}$

Q = reaction quotient = $\frac{[G_3P]}{[DHAP]}$

$[G_3P]$ = 0.06 M

[DHAP] = 0.125 M

Substituting the values into the equation yields:

$\Delta G=[-(8.314J/mol.K\times 298K\times \ln (5.4\times 10^{-2}))]+[(8.314J/mol.K\times 310K\times \ln (\frac{0.06}{0.125}))]\\\\\Delta G=-[-7231.46]+[-1891.7]=-5339.76J/mol$

Thus, the change in free energy for the reaction is -5339.76 J/mol

For B:

To convert the free energy change to kilojoules, we apply the conversion factor:

1 kJ = 1000 J

So, $-5339.76J/mol\times \frac{1kJ}{1000J}=-5.34kJ/mol$

Consequently, the free energy change's units are kJ/mol

For C:

For spontaneity in the reaction, the Gibbs free energy must be negative. However, the calculations indicate a positive Gibbs free energy, leading to the conclusion that the reaction is not spontaneous.

The free energy change of the reaction is negative.

Consequently, the forward reaction is favored and the reverse reaction is not favored.

8 0

1 month ago

Find the age ttt of a sample, if the total mass of carbon in the sample is mcmcm_c, the activity of the sample is AAA, the curre

castortr0y [2906]

Answer:

Explanation:

In a desert cave, an artifact has been discovered. The anthropologists investigating this artifact want to determine its age. They note that the current activity level of the artifact is 9.25 decays/s, and the carbon mass present is 0.100 kg. To ascertain the artifact's age, they will employ specific constants:

r=1.2

The formula for carbon 14 activity is

$A=A_0e^{\lambda t}$

where,

$A_0$ is the initial activity of the substance

Now, solve for t

$-\lambda t=In\frac{A}{A_0}$

$t=-\frac{1}{\lambda} In(\frac{A}{A_0} )$

$=-\frac{1}{\lambda} In(\frac{A}{\lambda r(\frac{m_c}{m_a} )} )$

since,

$A_0=\lambda r(\frac{m_c}{m_a} )$

$=-\frac{1}{\lambda} In(\frac{A\ m_a}{\lambda r m_c} )$

Thus, the age of the artifact is

$=-\frac{1}{\lambda} In(\frac{A\ m_a}{\lambda r m_c} )$

$=-\frac{1}{1.21\times 10^{-4}} In(\frac{(9.25)(2.32\times 10^{-26}}{1.21\times 10^{-4}(\frac{1}{3.15569\times10^7} )(1.2\times 10^{-12})(0.100)}} )\\\\=6303.4 \ years$

to two significant figures = 6300 years

4 0

1 month ago

4. Which of the following statements correctly describe atoms? Select all that apply.

castortr0y [2906]

Answer:

A, B, and C

Explanation:

Indeed, atoms possess mass and serve as the fundamental building blocks of chemical elements. While matter is composed of atoms, these particles themselves do not occupy physical space.

Atoms consist mostly of void, which excludes them from the other responses.

This confirms that A, B, and C are the right choices.

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1 month ago

What are the respective central-metal oxidation state, coordination number, and overall charge on the complex ion in Na2[Cr(NH3)

lions [2782]

Answer:

Central metal oxidation state: +2

Coordination number: 6

Overall charge: -2

Explanation:

For the ion complex:

Na₂[Cr(NH₃)₂(NCS)₄]

The central metal is chromium, with NH₃ and NCS as the ligands.

NH₃ acts as a neutral ligand, while NCS carries a negative charge.

The entire complex has a charge of:

2Na⁺ + [Cr(NH₃)₂(NCS)₄]⁻² → -2

Since each NCS contributes -1 and there are four NCS, the Cr must possess an oxidation state of +2 to achieve an overall charge of -2.

With 2 NH₃ and 4 NCS attached, the coordination number sums to 2+4 = 6

I trust this clarifies the matter!

6 0

1 month ago