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3 years ago

Scientific evidence shows that Earth's diameter, and thus overall size, does

Chemistry

1 answer:

Alex Ar [27]3 years ago

8 0

Answer:

The evidence goes against A. Expanding Earth and B. Contracting Earth

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How many valenence electons does sodium have?

olganol [36]

8 valence electrons :)

7 0

3 years ago

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The hydrogen chloride (HCl) molecule has an internuclear separation of 127 pm (picometers). Assume the atomic isotopes that make

natta225 [31]

Answer:

the energy of the third excited rotational state $\mathbf{E_3 = 16.041 \ meV}$

Explanation:

Given that :

hydrogen chloride (HCl) molecule has an intermolecular separation of 127 pm

Assume the atomic isotopes that make up the molecule are hydrogen-1 (protium) and chlorine-35.

Thus; the reduced mass μ = $\dfrac{m_1 \times m_2}{m_1 + m_2}$

μ = $\dfrac{1 \times 35}{1 + 35}$

μ = $\dfrac{35}{36}$

∵ 1 μ = 1.66 × 10⁻²⁷ kg

μ = $\\ \\ \dfrac{35}{36} \times 1.66 \times 10^{-27} \ \ kg$

μ = 1.6139 × 10⁻²⁷ kg

$r_o = 127 \ pm = 127*10^{-12} \ m$

The rotational level Energy can be expressed by the equation:

$E_J = \dfrac{h^2}{8 \pi^2 I } \times J ( J +1)$

where ;

J = 3 ( i.e third excited state) &

$I = \mu r^2_o$

$E_J= \dfrac{h^2}{8 \pi \mu r^ 2 \mur_o } \times J ( J +1)$

$E_3 = \dfrac{(6.63 \times 10^{-34})^2}{8 \times \pi ^2 \times 1.6139 \times 10^{-27} \times( 127 \times 10^{-12}) ^ 2 } \times 3 ( 3 +1)$

$E_3= 2.5665 \times 10^{-21} \ J$

We know that :

1 J = $\dfrac{1}{1.6 \times 10^{-19}}eV$

$E_3= \dfrac{2.5665 \times 10^{-21} }{1.6 \times 10^{-19}}eV$

$E_3 = 16.041 \times 10 ^{-3} \ eV$

$\mathbf{E_3 = 16.041 \ meV}$

8 0

3 years ago

Given the balanced equation representing a reaction:

notsponge [240]

Answer:

it is a base because they accept H+ ions

Explanation:

4 0

3 years ago

Which solution has the greatest number of hydroxide ions?

professor190 [17]

Baking soda. to put in the most simple terms..

-OH is the "base" anion
H+ is the "acid" ion

5 0

3 years ago

Read 2 more answers

During a spectrophotometric analysis of an unknown, you measure your solution's absorbance, and the value is higher than the hig

Reil [10]

Answer:

A) Dilute the unknown so that it will have an absorbance within the standard curve. Once the diluted unknown concentration is determined, the full strength concentration can be calculated if the dilution process is recorded. Beer's law only applies to dilute solutions, so diluting the unknown is better than making new standards.

Explanation:

Beer's law states that absorbance is proportional to the concentrations of the absorbing species. This is verified in the case of diluted solutions (0≤0.01 M) of most substances. As a solution gets more concentrated, solute molecules interact between themselves because of their proximity. When a molecule interacts with another, the change in their electric properties (including absorbance) is probable. That's why the plot of absorbance versus concentration stops being a straight line, and Beer's law is no longer valid.

Therefore, if the absorbance value is higher than the highest standard, dilutions should be made. Once this concentration is determined, the full strength concentration can be calculated with the inverse of the dilution.

7 0

3 years ago