ABS plastic is a tough, hard plastic used in applications requiring shock resistance. The polymer consists of three monomer units: acrylonitrile \(\left(\mathrm{C}_{3} \mathrm{H}_{3} \mathrm{~N}\right)\), butadiene \(\left(\mathrm{C}_{4} \mathrm{H}_{6}\right)\), and styrene \(\left(\mathrm{C}_{8} \mathrm{H}_{8}\right)\). a. A sample of ABS plastic contains \(8.80 \% \mathrm{~N}\) by mass. It took \(0.605 \mathrm{~g}\) of \(\mathrm{Br}_{2}\) to react completely with a \(1.20-\mathrm{g}\) sample of ABS plastic. Bromine reacts \(1: 1\) (by moles) with the butadiene molecules in the polymer and nothing else. What is the percent by mass of acrylonitrile and butadiene in this polymer? b. What are the relative numbers of each of the monomer units in this polymer?

We are given that the sample of ABS plastic contains 8.80% N by mass. Therefore, in a 1.20-g sample of ABS plastic, we can find the mass of nitrogen (N) using this percentage: Mass of N = (8.80 / 100) * 1.20 g ##Step 2: Calculate the moles of acrylonitrile monomer##

Acrylonitrile has the molecular formula C3H3N. The molar mass of acrylonitrile is: Molar mass of C3H3N = (3 * 12.01 g/mol) + (3 * 1.01 g/mol) + (1 * 14.01 g/mol) Since there is only one nitrogen atom in each acrylonitrile molecule, we can find the moles of acrylonitrile in the sample: Moles of acrylonitrile = (mass of N) / (molar mass of N in C3H3N) ##Step 3: Calculate the mass of acrylonitrile in the polymer##

Now, we can calculate the mass of the acrylonitrile in the polymer using the moles of acrylonitrile: Mass of acrylonitrile = moles of acrylonitrile * molar mass of C3H3N ##Step 4: Calculate the moles of butadiene monomer##

We are given that it took 0.605 g of Br2 to react completely with the butadiene present in the polymer. We are also given that bromine reacts 1:1 (by moles) with the butadiene molecules. First, let's calculate the moles of Br2 that reacted: Molar mass of Br2 = 2 * 79.90 g/mol Moles of Br2 = (0.605 g) / (molar mass of Br2) Since Bromine reacts 1:1 (by moles) with butadiene, the moles of butadiene would be equal to the moles of Br2. Moles of butadiene = moles of Br2 ##Step 5: Calculate the mass of butadiene in the polymer##

We can now calculate the mass of the butadiene in the polymer using the moles of butadiene we just calculated: Molar mass of C4H6 = (4 * 12.01 g/mol) + (6 * 1.01 g/mol) Mass of butadiene = moles of butadiene * molar mass of C4H6 ##Step 6: Calculate the percent by mass of acrylonitrile and butadiene in the polymer##

We can now calculate the percent by mass of acrylonitrile and butadiene in the polymer using their respective masses: Percent by mass of acrylonitrile = (mass of acrylonitrile / total mass of the sample) * 100 Percent by mass of butadiene = (mass of butadiene / total mass of the sample) * 100 After calculating the percentages, this answers part (a) of the question. #Step 7: Calculate the relative numbers of each of the monomer units in the polymer##

To find the relative numbers of each of the monomer units, let's divide the moles of acrylonitrile, butadiene, and styrene by the smallest number of moles found. First, we will calculate the moles of styrene. We know the total mass of the polymer is 1.20 g. Subtract the mass of acrylonitrile and butadiene to find the mass of styrene: Mass of styrene = total mass of the sample - (mass of acrylonitrile + mass of butadiene) Now calculate the moles of styrene: Molar mass of C8H8 = (8 * 12.01 g/mol) + (8 * 1.01 g/mol) Moles of styrene = mass of styrene / molar mass of C8H8 Now divide the moles of acrylonitrile, butadiene, and styrene by the smallest number of moles found among the moles of these monomer units. This would give a whole-number ratio of the moles of acrylonitrile, butadiene, and styrene in the polymer. This answers part (b) of the question.