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4 years ago

Calculate the number-average molecular weight for a poly(vinyl chloride) for which the degree of polymerization is 21500.

Chemistry

1 answer:

bezimeni [28]4 years ago

4 0

Answer:

The number-average molecular weight for a poly(vinyl chloride) is 1,343,750 g/mol.

Explanation:

Molecular weight of the poly(vinyl chloride), $CH_2=CHCl =M=62.5 g/mol$

Number average molecular weight of the polymer = M_a

Degree of polymerization = n = 21500

$\frac{M_a}{M}=n$

$M_a=n\times m=21500\times 62.5 g/mol=1,343,750 g/mol$

The number-average molecular weight for a poly(vinyl chloride) is 1,343,750 g/mol.

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Answer:

- 622.5kJ

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2) 2NH3 + 3N2O ----> 4N2 + 3H2O ΔH° 1= - 1010kJ

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2NH3 + 3N2H4 --->4N2+9H2, ΔH° 1 - 3*ΔH° 2

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N2H4 +O2 --->N2+2H2O, 1/4( ΔH° 1 - 3*ΔH° 2 - ΔH°3 + 9*ΔH° 4)

N2H4 +O2 --->N2+2,

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3 years ago

When 551. mg of a certain molecular compound X are dissolved in 100 g of benzonitrile (CH,CN), the freezing point of the solutio

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Answer:

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The pure benzonitrile has freezing point -12.8°C. By adding a nonvolatile compound, the freezing point will be changed, a process called cryoscopy. The freezing point will be reduced. In this case, the new freezing point is -13.4°C. The variation at the temperature can be calculated by the equation:

ΔT = Kc*W*i

Where ΔT is the variation at the freezing temperature (without the solute less with the solute), Kc is the cryoscopy constant (5.34 for benzonitrile), W is the molality, and i the Van't Hoff correction factor, which is 1 for benzonitrile.

((-12.8-(-13.4)) = 5.34*W

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W = m1/M1*m2

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0.1124 = 0.551/M1*0.1

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