3 years ago

What does the atomic number tell you about the element

1 answer:

4 0

It tells you how many protons it has and because the number of protons =electrons it tells you also the number of electrons.

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Calculate the wavelength, in nanometers, of the light emitted by a hydrogen atom when its electron fallsfrom the n = 7 to the n

Helga [31]

Answer:

λ=2167.6 nm

The wavelength of light emitted is 2167.6 nm.

Explanation:

We recall that Eₙ= $\frac{-2.18*10^{-18} J}{n^{2} }$

since there was transition from n7 to n=4 we will first calculate the change in the energy i.e ΔE

ΔE=E₄-E₇

ΔE= $-2.18*10^{-18} J(\frac{1}{4^{2} } -\frac{1}{7^{2} } )$

ΔE=-9.1760*10^-20 J

Now:

|ΔE|=Energy of photon=h*v=h*c/λ

λ=h*c/|ΔE|

λ= $\frac{6.63*10^{-34}J.s*3.00*10^{8}m/s }{9.1760*10^{-20} J }$

λ=2.1676*10^-6 m

λ=2167.6*10^-9 m

λ=2167.6 nm

The wavelength of light emitted is 2167.6 nm.

5 0

4 years ago

If 16.0 mL of acetone is dissolved in water to make 155 mL of solution what is the concentration expressed in volume/volume % of

Lady_Fox [76]

Percentage by volume of solution is the percentage volume of solute in total volume of solution.
Volume percentage (v/v%) = volume of solute / total volume of solution x 100%
volume of solute - 16.0 mL
total volume of solution - 155 mL
v/v% = 16.0 / 155 x 100% = 10.32%
this means that in a volume of 100 mL solution, 10.32 mL is acetone.

7 0

3 years ago

Can the work output of an engine be greater than the source of energy.

Arlecino [84]

Answer:

Explanation:

the output can never be greater than the input

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3 years ago

"Given a block of frozen salt water, how could you separate

cricket20 [7]

Answer: You could put the frozen block of ice on the stove and let it melt and eventually boil out leaving the salt behind

Explanation:

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3 years ago

At which part of a river would you have the best luck growing food?

krek1111 [17]

Answer:

B. Delta

Explanation:

3 0

3 years ago

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