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elixir [45]
3 years ago
15

Calculate the number-average molecular weight of a random nitrile rubber [poly(acrylonitrile-butadiene) copolymer] in which the

fraction of butadiene repeat units is 0.27; assume that this concentration corresponds to a degree of polymerization of 2000.
Chemistry
1 answer:
SCORPION-xisa [38]3 years ago
7 0

Answer:

106,504 g/mol

Explanation:

The two repeat units at the polymer are the acrylonitrile and the butadiene. If the fraction of repeat of butadiene is 0.27, the fraction of repeat of units of acrylonitrile must be 0.73.

The acrylonitrile repeat unit has 3 carbons atoms, 1 nitrogen atom, and 3 hydrogen atoms. So, the molecular weigth for it is:

mac = 3*mC + 1*mN + 3*mH

mC = 12 g/mol; mN = 14 g/mol; mH = 1g/mol

mac = 3*12 + 14 + 3*1 = 53 g/mol

The butadiene repeat unit has 4 carbons atoms and 6 hydrogen atoms. Thus, the molecular weight is:

mbu = 4*12 + 6*1 = 54 g/mol

The average repeat unit molecular weight is the fractions multiplied by the molecular weight of the repeat unities:

m = 0.73*53 + 0.27*54 = 53.27 g/mol

The number-average molecular weight is the average repeat unit molecular weight  multiplied by the degree of polymerization:

M = 53.27*2000

M = 106,504 g/mol

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3 years ago
Why does galium melt
levacccp [35]

Answer:

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- It melts once it reaches its melting point.

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7 0
3 years ago
Which describes an impermeable rock where oil and natural gas deposits are found?
love history [14]

Answer:

Explanation:

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5 0
3 years ago
How many atoms of oxygen are present in 7.51 grams of<br> glycine with formula C₂H5O2N?
Blizzard [7]

1.205 × 10²³ atoms of oxygen will be present in 7.51 grams of glycine with formula C₂H5O2N. Details about number of atoms can be found below.

How to calculate number of atoms?

The number of atoms of a substance can be calculated by multiplying the number of moles of the substance by Avogadro's number.

However, the number of moles of oxygen in glycine can be calculated using the following expression:

Molar mass of C₂H5O2N = 75.07g/mol

Mass of oxygen in glycine = 32g/mol

Hence; 32/75.07 × 7.51 = 3.2grams of oxygen in glycine

Moles of oxygen = 3.2g ÷ 16g/mol = 0.2moles

Number of atoms of oxygen = 0.2 × 6.02 × 10²³ = 1.205 × 10²³ atoms

Therefore, 1.205 × 10²³ atoms of oxygen will be present in 7.51 grams of glycine with formula C₂H5O2N.

Learn more about number of atoms at: brainly.com/question/8834373

#SPJ1

3 0
2 years ago
You drop an unknown substance that weighs 8.3g into a graduated cylinder with 6ml of water. The water rises to 8ml when you drop
valkas [14]

Answer:

<h3>The answer is 4.15 g/mL</h3>

Explanation:

The density of a substance can be found by using the formula

density =  \frac{mass}{volume} \\

From the question

mass of object = 8.3 g

volume = final volume of water - initial volume of water

volume = 8 - 6 = 2 mL

So we have

density =  \frac{8.3}{2}  \\

We have the final answer as

<h3>4.15 g/mL</h3>

Hope this helps you

7 0
4 years ago
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