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bogdanovich [222]
3 years ago
4

The absorbance features observed in the visible spectrum for curcumin is a result of an allowed optical excitation of an electro

n from the π-HOMO to the π*-LUMO. What is the energy change for this electronic excitation based on the spectrum? (Hint: Energy and wavelength are related by the equation E = hc/λ.) h = 4.136 × 10-15 eV⋅ s c = 2.998 × 108 m/s

Chemistry
1 answer:
Virty [35]3 years ago
4 0

Answer:

2.3 ev or 3.68 ×10^-19J

Explanation:

The spectrum is shown in the image attached

h= 4.136 × 10-15 eV⋅ s

c = 2.998 × 108 m/s

λmax= 550×10^-9 (from the spectrum attached)

E=hc/λmax

E= 4.136 × 10^-15 × 2.998 × 10^8/550×10^-9

E= 2.3 ev or 3.68 ×10^-19J

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Find the [h3o ] in a sauvignon blanc with a ph of 3.24.
KengaRu [80]
Hello!

The H₃O⁺ concentration can be found using the definition of pH and clearing the equation for [H₃O⁺]. The solution has a pH lower than 7, so the Sauvignon Blanc is acid. The calculation for [H₃O⁺] is shown below:

pH=-log [H_3O^{+}]

[H_3O^{+}]= 10^{-pH}=10^{-3,24}=0,00058M

So, the concentration of H₃O⁺ in a Sauvignon Blanc with a pH of 3,24 is 0,00058 M

Have a nice day!
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3 years ago
What are the total balance electrons? <br> PHOTO ABOVE
WINSTONCH [101]

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Hope this helped! :)

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3 years ago
What is a diagnostic characteristic of a mineral used to make a cement slab in your house?
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3 years ago
Calculate the [H+] and pH of a 0.000185 M acetic acid solution. Keep in mind that the Ka of acetic acid is 1.76×10−5. This is a
lisov135 [29]

Answer:

[H⁺] = 0.000048936M

pH = 4.31

Explanation:

Acetic acid, CH₃COOH, dissociates in water as follows:

CH₃COOH(aq) ⇄ H⁺(aq) + CH₃COO⁻(aq)

And Ka is defined as:

Ka = 1.76x10⁻⁵ =  [H⁺] [CH₃COO⁻] / [CH₃COOH]

<em>Where [] are equilibrium concentrations of the species.</em>

<em />

The 0.000185M of acetic acid will decreases X, and X of [H⁺] and [CH₃COO⁻] will be produced. That means Ka is:

1.76x10⁻⁵ =  [X] [X] / [0.000185 - X]

3.256x10⁻⁹ - 1.76x10⁻⁵X = X²

3.256x10⁻⁹ - 1.76x10⁻⁵X - X² = 0

Solving for X:

X = -0.000066M → False solution. There is no negative concentrations.

X = 0.000048936

As [H⁺] = X,

[H⁺] = 0.000048936M

And pH = -log [H⁺]

<h3>pH = 4.31</h3>

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3 years ago
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4 years ago
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