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4 years ago

I need help solving this for chemistry. Don’t know where to start:/

Chemistry

1 answer:

Juli2301 [7.4K]4 years ago

8 0

1 electron has charge =1.602* 10⁻¹⁹ C
1 mole of electrons have 1.602* 10⁻¹⁹*6.02*10²³C = 9.64*10⁴ C/1mol

One ion Co²⁺ takes 2e⁻ to become Co⁰.
1 mol of Co²⁺ ions take 2 mole of e⁻ to become Co⁰, so
0.30 mol Co²⁺ ions take mole of 0.60 mol e⁻ to become Co⁰

9.64*10⁴(C/1mol) *0.60 (mol)≈ 5.8 *10⁴ Coulombs.
Correct answer is C

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Explanation:

Given that

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We know that in FCC structure ,in FCC 8 atoms at corner with 1/8 th part in one unit cell and 6 atoms at faces with 1/2 part in one unit cell .

Z=8 x 1/8 + 1/2 x 6 =4

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The number of atoms which touch the second atoms is known as coordination number.In other word the number of nearest atoms.

CN=12

Coordination number of FCC structure is 12.These 12 atoms are 4 atoms at the at corner ,4 atoms at 4 faces and 4 atoms of next unit cell.

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$APF=\dfrac{Z\times \dfrac{4}{3}\pi R^3}{a^3}$

We know that for FCC

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Now by putting the values

$APF=\dfrac{4\times \dfrac{4}{3}\pi R^3}{\left(\dfrac{4R}{\sqrt2}\right)^3}$

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Density

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M=58.69 g/mol

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$N_A=6.023\times 10^{23}\ atom/mol$

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