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Nikolay [14]
3 years ago
15

PLS PLS PLS PLS HELP IM STRUGGLING

Chemistry
1 answer:
andriy [413]3 years ago
5 0

Answer:

A. 4 only

Explanation:

One of the tests for purity is by determining the melting point of a substance. A pure substance has a sharp meting point.

If the solid in question is a pure solid, when it is heated, it will exhibit a sharp melting point. Mixtures however melt over a range of temperatures due to the presence of impurities in the solid.

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Calculate the energy, in joules, required to ionize a hydrogen atom when its electron is initially in the n =2 energy level. The
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Answer:

E_{ionization}=5.45\times 10^{-19}\ J

Explanation:

E_n=-2.18\times 10^{-18}\times \frac{1}{n^2}\ Joules

For transitions:

Energy\ Difference,\ \Delta E= E_f-E_i =-2.18\times 10^{-18}(\frac{1}{n_f^2}-\frac{1}{n_i^2})\ J=2.18\times 10^{-18}(\frac{1}{n_i^2} - \dfrac{1}{n_f^2})\ J

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Thus,

\Delta E=2.18\times 10^{-18}(\frac{1}{2^2} - \dfrac{1}{{\infty}^2})\ J

\Delta E=2.18\times 10^{-18}(\frac{1}{2^2})\ J

E_{ionization}=5.45\times 10^{-19}\ J

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