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3 years ago

HELP!!!!!! 40 POINTS!!!!!!

Chemistry

2 answers:

olga_2 [115]3 years ago

6 0

Answer:

The correct answer is A.

Explanation:

Have a good day!

elena55 [62]3 years ago

3 0

Answer:

its B its B its B its B

Explanation:

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Which of the following electron transitions in a hydrogen atom emits light of the shortest wavelength? Circle the correct answer

Lilit [14]

Answer:

Transition from n = 4 to n = 1 corresponds to shortest wavelength.

Explanation:

Process $\mid \Delta n\mid =\mid \frac{1}{(n)_{final}^{2}}-(\frac{1}{n_{initial}^{2}})\mid$

A 0.9375

B 0.75

C 0.0421

D 0.1875

According to Rydberg equation for electronic transition in H-like atoms:

$\frac{1}{\lambda }=R_{H}\mid (\frac{1}{n_{final}^{2}}-(\frac{1}{n_{initial}^{2}})\mid$

where, $\lambda$ is wavelength of light emitted or absorbed, $R_{H}$ is Rydberg constant.

So, higher the value of $\mid \Delta n\mid$ , lower will the corresponding wavelength of light.

Hence process A will be associated with shortest wavelength.

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3 years ago

Moseley's changes to the periodic table were based mainly on what part of the scientific process

ale4655 [162]

I believe the answer is observation of the elements

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3 years ago

The chemical formula for sodium sulfate

shtirl [24]

The charge of Na ion is~

${na}^{ + }$

7 0

3 years ago

Consider Al at room temperature. Its electron density is n = 18 x 1022 cm-3 and its electrical resistivity is rho = 2.45 μΩ-cm.

Marianna [84]

Answer:

$\tau=1.28968\times 10^{-8}\ s$ is the electron relaxation time

$l=9.6726\times 10^{-4}\ m$ is the mean free path

Explanation:

Given:

electron density of aluminium at room temperature, $n=18\times 10^{22}\ cm^{-3}$

resistivity of aluminium, $\rho=2.45\times 10^{-8}\ \Omega.m$

<u>From the Drude's model we have:</u>

$\tau=\frac{m}{\rho.n.q^2}$

where:

$\tau=$ electron relaxation time

$m=$ mass of a charge

$q=$ magnitude of a charge

Putting respective values for electron:

$\tau=\frac{9.1\times 10^{-31}}{2.45\times 10^{-8}\times 18\times 10^{22}\times (1.6\times 10^{-19})^2}$

$\tau=8.0605\times 10^{-9}\ s$

<u>Mean free path is given as:</u>

$l=v_a.\tau$

where:

$l=$ mean free path

$v_a=$ average velocity of electrons

Now we have the the general value of average velocity of electrons at room temperature:

$v_a=120000\ m.s^{-1}$

So,

$l=120000\times 8.0605\times 10^{-9}$

$l=9.6726\times 10^{-4}\ m$

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3 years ago

Something that is made of all the same atoms or groups of atoms

nekit [7.7K]

Answer:

I think it's a molecule...

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3 years ago

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