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4 years ago

What does light do in the photoelectric effect?

Chemistry

1 answer:

Trava [24]4 years ago

4 0

Answer:

it's B: light knocks electrons off metal atoms

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Calculate the nuclear binding energy for 5525mn in megaelectronvolts per nucleon (mev/nucleon). express your answer numerically

VARVARA [1.3K]

Answer:

8.533 Mev/nucleon

Explanation:

The given elements is:- $^{55}_{25}Mn$

Atomic number : It is defined as the number of electrons or number of protons present in a neutral atom.

Thus, the number of protons = 25

Mass number is the number of the entities present in the nucleus which is the equal to the sum of the number of protons and electrons.

Mass number = Number of protons + Number of neutrons

55 = 25 + Number of neutrons

Number of neutrons = 30

Mass of neutron = 1.008665 amu

Mass of proton = 1.007825 amu

Calculated mass = Number of protons*Mass of proton + Number of neutrons*Mass of neutron

Thus,

Calculated mass = (25*1.007277 + 30*1.008665) amu = 55.441875 amu

Actual mass = 54.9380451 amu

Mass defect = Δm = |54.9380451 - 55.441875| amu = 0.5038299 amu

The conversion of amu to MeV is shown below as:-

1 amu = 931.5 MeV

So, Energy = 0.5038299*931.5 MeV= 469.317552 MeV

Total number of nucleons in the atoms = 55

<u>So, Energy = 469.317552/55 MeV/nucleon = 8.533 Mev/nucleon</u>

5 0

4 years ago

Nitrogen bases are molecules that contain nitrogen and other elements

Bogdan [553]

True it also contains oxygen

3 0

3 years ago

How many moles in 68.1 grams of Cu(OH)2

Andrew [12]

To do this, you would first add together the molar mass of all involved elements, to find how many grams are in a mole of Cu(OH)2. Keep in mind, the molar mass is equal to the atomic mass of an element in grams. For example the molar mass of copper (Cu) would be 63.55 (with 2 sig. figs.)

Therefore, now we add together the mass of all elements involved.

Cu: (63.55)+O2(15.99x2=31.98)+H2(1.01x2=2.02)

63.55+31.98+2.02= 97.55g per mole of Cu(OH)2.

Now, divide what we have by how much it takes to get a mole of the stuff.

68.1/97.55= 0.698mol Cu(OH)2

6 0

3 years ago

Are all lenses planer?

skelet666 [1.2K]

no all lenses aren't plan

3 0

3 years ago

What is the pH of a solution that is 0.10 M formic acid and 0.0065 M formate (the conjugate base)? Ka of formic acid = 1.77 x 10

Dima020 [189]

Answer:

pH = 2.56

Explanation:

The Henderson-Hasselbalch equation relates the pH to the Ka and ratio of the conjugate acid-base pair as follows:

pH = pKa + log([A⁻]/[HA]) = -log(Ka) + log([A⁻]/[HA])

Substituting in the value gives:

pH = -log(1.77 x 10⁻⁴) + log((0.0065M) / (0.10M))

pH = 2.56

3 0

3 years ago