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ziro4ka [17]
3 years ago
14

"A crosslinked copolymer consists of 57 wt% ethylene (C2H4) repeat units and 43 wt% propylene (C3H6) repeat units. Determine the

fraction of (a) ethylene and (b) propylene repeat units."
Chemistry
1 answer:
ch4aika [34]3 years ago
3 0

Explanation:

Percentage ethylene by weight = 57%

Percentage propylene by weight = 43%

Suppose in 100 grams of polymer:

Mass of ethylene = 57 g

Mass of propylene = 43 g

Moles of ethylene = \frac{57 g}{28 g/mol}=2.036 mol

Moles of propylene = \frac{43g}{42g/mol}=1.024 mol

1 mole = N_A =6.022\times 10^{23} molecules/ atoms

Units of ethylene = 2.036 mol\times N_A

Units of propylene = 1.024 mol\times N_A

a) Fraction of ethylene units:

=\frac{2.036 mol\times N_A}{2.306 mol\times N_A+1.024 mol\times N_A}=\frac{509}{765}

b ) Fraction of propylene units:

=\frac{1.024mol\times N_A}{2.306 mol\times N_A+1.024 mol\times N_A}=\frac{256}{765}

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