Answer:
0.0164 g
Explanation:
Let's consider the reduction of silver (I) to silver that occurs in the cathode during the electroplating.
Ag⁺(aq) + 1 e⁻ → Ag(s)
We can establish the following relations.
- 1 A = 1 C/s
- The charge of 1 mole of electrons is 96,468 C (Faraday's constant)
- 1 mole of Ag(s) is deposited when 1 mole of electrons circulate.
- The molar mass of silver is 107.87 g/mol
The mass of silver deposited when a current of 0.770 A circulates during 19.0 seconds is:

69.9%
Explanation:
To find the mass percentage of iron in the compound in Fe₂O₃, we would go ahead to express the given molar mass of the iron to that of the compound.
Mass percentage =
x 100
Molar mass of Fe = 55.85g/mol
Molar mass of O = 16g/mol
Molar mass of Fe₂O₃ = 2(55.85) + 3(16) = 159.7g/mol
Mass percentage =
= 69.94% = 69.9%
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The decreasing order of wavelengths of the photons emitted or absorbed by the H atom is : b → c → a → d
Rydberg's formula :
,
where λ is the wavelength of the photon emitted or absorbed from an H atom electron transition from
to
and
= 109677 is the Rydberg Constant. Here
and
represents the transitions.
(a)
=2 to
= infinity
= 109677/4 [since 1/infinity = 0] Therefore,
= 4 / 109677 = 0.00003647 m
(b)
=4 to
= 20
= 6580.62
Therefore,
= 1 / 6580.62 = 0.000152 m
(c)
=3 to
= 10
= 11089.56
Therefore,
= 1 / 11089.56 = 0.00009 m
(d)
=2 to
= 1
= - 82257.75
Therefore,
= 1 /82257.75 = - 0.0000121 m
[Even though there is a negative sign, the magnitude is only considered because the sign denotes that energy is emitted.]
So the decreasing order of wavelength of the photon absorbed or emitted is b → c → a → d.
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The chemical element of atomic number 7, a colorless, odorless unreactive gas that forms
about 78 percent of the earth's atmosphere.