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Olenka [21]
4 years ago
15

The unit cells can be represented by tennis balls arranged in various configurations in a box. For the FCC structure, (a) determ

ine the lattice constant a in terms of atomic radius R, and (b) show the atomic packing factor (APF) is 0.74.

Chemistry
1 answer:
-Dominant- [34]4 years ago
3 0

Based on the diagram shown in the attached file

R = Radius of the sphere  

a = Lattice constant

Using pythagoras theorem for the right angled triangle in figure 2

(4R)^2 = a^2 + a^2

16(R^2) = 2(a)^2

Solving the above equation

a=2R√2

To prove that the Atomic Packing factor is 0.74

Let the volume of atom in a unit cell be Vs

Total unit cell volume, Vc  

Vc = a^3

Vc =(2R√2)^3

Vc=16R^3 √2  =22.63R^3

Since there are 4 atoms in the FCC unit cell

Vs=4*(4/3 πR^3)

Vs=5.33 πR^3

APF=(5.33 πR^3)/(22.63R^3 )

APF=0.74

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Answer:

0.0159m

Explanation:

9 M

Explanation:

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Instead of dissociating completely, an equilibrium rection governed by the solubility product constant,  

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Now, the molar solubility of the compound,  

s

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Notice that every mole of lead(II) chloride will produce  

1

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moles of chloride anions. Use an ICE table to find the molar solubility of the solid

 

PbCl

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⇌

 

Pb

2

+

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+

 

2

Cl

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I

 

 

 

−

 

 

 

 

 

0

 

 

 

 

 

0

C

 

 

x

−

 

 

 

 

(+s)

 

 

 

 

(

+

2

s

)

E

 

 

x

−

 

 

 

 

 

s

 

 

 

 

 

2

s

By definition, the solubility product constant will be equal to

K

sp

=

[

Pb

2

+

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⋅

[

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−

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2

K

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(

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s

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2

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s

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4

s

3

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10

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8 0
3 years ago
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Alex787 [66]
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7 0
3 years ago
How many grams of coffee must evaporate from 350 g of coffee in a 100-g glass cup to cool the coffee and the cup from 95.0°C to
Natali5045456 [20]

Answer:

31.3 g

The answer is higher than the true answer.

Explanation:

By neglecting the heat lost by other processes, the energy conservation states that:

Qcooling + Qevaporate = 0

The cooling process happens without phase change, so the heat can be calculated by:

Qcooling = m*c*ΔT

Where m is the mass, c is the heat capacity (cwater = 4184 J/kg.K), and ΔT is the temperature variation (final - initial).

The evaporate process happen without changing of temperature (pure substance), and the heat can be calculated by:

Qevaporate = m*L

Where m is the mass evaporated and L is the heat of evaporation (2340000 J/kg).

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m = 0.0313 kg

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Because of the assumptions made, the real mass is not that was calculated. There'll be changing mass when the coffee is cooling, and there'll be heat loses by other processes because the system is not isolated. Also, the substance is not pure. So, there'll be more factors at the energy equation, thus, the answer is higher than the true answer.

6 0
4 years ago
What does the prefix trans-indicate?
fredd [130]

Answer:

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7 0
3 years ago
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Answer:

C

Explanation:

Of course increasing the pressure will reduce the volume

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P1V1/P2 = V2     WHEN P2 = 2 P1----multiply both sides by 1/2

P1 V1 / 2P1 = 1/2 V2    <===== 1/2 the original

8 0
2 years ago
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