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Korvikt [17]
3 years ago
5

Select the sentences in the paragraph that explain only the dark lines that are produced in the absorption spectra. Select all t

hat apply.
A light is shown through a cold, dilute gas. Over time, excited atoms revert to their original lower energy state. Photons emitted travel in different directions that the original photon. Gaps are produced in the light spectra that correspond to wavelengths of absorbed photons. Dark lines in an absorption spectrum of light can be seen when the gas lies between the light source and observer.
Chemistry
1 answer:
Nady [450]3 years ago
5 0

Answer:

Gaps are produced in the light spectra that correspond to wavelengths of absorbed photons.

Explanation:

When electrons in atoms absorb energy, they move from a lower energy level to a higher energy level. With time, they revert to the their original energy state emitting a photon of light of appropriate wavelength.

The absorbed photons do not show up in the spectrum. They appear as dark lines in the spectrum. Hence, the absorption spectrum is the exact inverse of the emission spectrum. The  dark lines in the spectrum indicates that the colors that ought to occupied those points there have been absorbed.

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The question is on the picture.
nydimaria [60]
Density is typically the best way to determine the chemical property because almost always it is unique.
6 0
3 years ago
Calculate the percent ionization of formic acid (hco2h) in a solution that is 0.311 m in formic acid and 0.189 m in sodium forma
ohaa [14]
<span>Answer: 0.094%


</span><span>Explanation:
</span>
<span></span><span /><span>
1) Equilibrium chemical equation:
</span><span />

<span>Only the ionization of the formic acid is the important part.
</span><span />

<span>HCOOH(aq) ⇄ HCOO⁻(aq) + H⁺(aq).
</span><span />

<span>2) Mass balance:
</span><span />

<span>                   HCOOH(aq)     HCOO⁻(aq)     H⁺(aq).

Start             0.311                 0.189

Reaction       - x                      +x                   +x

Final             0.311 - x          0.189 + x            x


3) Acid constant equation:
</span><span />

<span>Ka = [HCOO-] [N+] / [HCOOH] = (0.189 + x) x / (0.311 -x)
</span><span />

<span>= (0.189 + x )x / (0.311 - x) = 0.000177


4) Solve the equation:


You can solve it exactly (it will lead to a quadratic equation so you can use the quadratiic formula). I suggest to use the fact that x is much much smaller than 0.189 and 0.311.
</span><span />

<span>With that approximation the equation to solve becomes:


</span><span>0.1890x / 0.311 = 0.000177, which leads to:</span>
<span /><span>
x = 0.000177 x 0.311 / 0.189 = 2.91 x 10⁻⁴ M


5) With that number, the percent of ionization (alfa) is:
</span><span />

<span>percent of ionization = (moles ionized / initial moles) x 100 =
</span><span>
</span><span>
</span><span>percent ionization = (concentration of ions / initial concentration) x 100 =
</span><span>
</span><span>
</span><span>percent ionization = (0.000291 / 0.311)x 100 = 0.0936% = 0.094%
</span>
<span></span><span />
8 0
3 years ago
In the reaction MgCI2+ 2KOH —&gt; Mg(OH)2 + 2KCI if 6 moles MgCI2 are added to 6 miles KOH which is the limiting reagent
Ratling [72]

KOH is the limiting reagent

The molar ratio is 1:2

So if you have 6 moles of MgCl2 you need 12 moles of KOH

7 0
4 years ago
In the three-dimensional structure of methane, ch4, the hydrogen atoms attached to a carbon atom are aligned ________. in the th
Nikitich [7]
Answer:
            In the three-dimensional structure of methane, CH₄, the hydrogen atoms attached to a carbon atom are aligned <span><u>at the corners of a Tetrahedron</u>.

Explanation:
                   In Methane (CH</span>₄) the central atom (carbon) is bonded to four hydrogen atoms. So, the central atom is having four electron pairs and all pairs are bonding pairs and lacks any lone pair of electron. According to Valence Shell Electron Pair Repulsion (VSEPR) Theory the central atom with four bonding pair electrons and zero lone pair electrons will attain a tetrahedral geometry with bond angles of 109°. Hence, the shape of CH₄ is tetrahedral.

4 0
3 years ago
When the oxidation number of an element decreases over the course of a reaction, that element has beenWhich of the following che
NARA [144]
AgNO3+NaCl yields AgCl+NaNo3 (reduction)
...that's the only one I know
4 0
3 years ago
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