A low molecular weight biopolymer is being investigated for its suitability for medical use - HSC - SSCE Chemistry - Question 18 - 2022 - Paper 1

To determine which option produces a suitable biopolymer, we need to calculate the molecular weight based on the number of units provided. The target molecular weight is 2900 g mol⁻¹ with a tolerance of ± 100 g mol⁻¹.

Calculating the Molecular Weight:

1. Option A:

   • Molar mass = 88.01 g mol⁻¹
   • Number of units = 42
   • Total molecular weight = $88.01 imes 42 = 3694.42 ext{ g mol}^{-1}$
   • This exceeds the optimum weight.

2. Option B:

   • Molar mass = 88.01 g mol⁻¹
   • Number of units = 33
   • Total molecular weight = $88.01 imes 33 = 2904.33 ext{ g mol}^{-1}$
   • This also exceeds the optimum weight.

3. Option C:

   • Molar mass = 90.078 g mol⁻¹
   • Number of units = 32
   • Total molecular weight = $90.078 imes 32 = 2882.49 ext{ g mol}^{-1}$
   • This value is acceptable as it is within the range (2900 ± 100).

4. Option D:

   • Molar mass = 90.078 g mol⁻¹
   • Number of units = 40
   • Total molecular weight = $90.078 imes 40 = 3603.12 ext{ g mol}^{-1}$
   • This exceeds the optimum weight.

Conclusion:

The suitable biopolymer that meets the molecular weight criteria of 2900 ± 100 g mol⁻¹ is Option C, as it has a total molecular weight of 2882.49 g mol⁻¹.