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3 years ago

I’m confused because this is the answer key and I don’t know how they got the answer to number 1)

Chemistry

1 answer:

Tems11 [23]3 years ago

5 0

Question One

It's more a question of unscrambling what is there. The answer is correct.

If you look at your periodic table, there is such an element as Na which I suspect might be the problem.

It has an atomic mass of 23. It's atomic number is 11 which means it is the 11th member (by mass) on the periodic table. The other 2 are oxygen and hydrogen. So Oxygen has an atomic mass of 16 and Hydrogen has an atomic mass of 1.

Oxygen is number 8 on the periodic table and hydrogen is number 1.

Molecular Mass

Na = 23

O = 16

H = 1

Total 40, just as the answer key says. I've probably given you more than you wanted to know, but if you still have trouble, leave a note.

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When an excited electron in a hydrogen atom falls from ????=5 to ????=2, a photon of blue light is emitted. If an excited electr

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Answer:

n = 3

Explanation:

Given the formula for the transition energy of an atom with 1 electron:

$E=-13.6*Z^{2}*(\frac{1}{n_{f}^{2}}-\frac{1}{n_{i}^{2}} ) eV$

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$n_{f}=\sqrt{\frac{n_{i}^{2}*Z^{2}*13.6 eV }{2.856eV*n_{i}^{2}+13.6eV*Z^{2}} }$

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4 0

3 years ago

An element consists of two isotopes. The abundance of one isotope is 95.72% and its atomic mass is 114.9041 u. The atomic mass o

meriva

Answer:

d. 114.8 u

Explanation:

The formula for the calculation of the average atomic mass is:

$Average\ atomic\ mass=(\frac {\%\ of\ the\ first\ isotope}{100}\times {Mass\ of\ the\ first\ isotope})+(\frac {\%\ of\ the\ second\ isotope}{100}\times {Mass\ of\ the\ second\ isotope})$

Given that:

For first isotope:

% = 95.72 %

Mass = 114.9041 u

For second isotope:

Since the element has only 2 isotopes, so the percentage of second is 100 - first percentage.

% = 100 % - 95.72 % = 4.28 %

Mass = 112.9043 u

Average Mass = ?

Thus,

$Average\ atomic\ mass=\frac {95.72}{100}\times {114.9041}+\frac {4.28}{100}\times {112.9043}\ u$

Average atomic mass = 114.8 u

3 0

3 years ago

Please Help!

olga2289 [7]

Answer:

33.2 psi

Explanation:

Given data:

Pressure of car = 229 KPa

Pressure in Psi = ?

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We will convert the pressure into atm first.

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3 years ago