Answer:
21,200g/mol
Explanation:
General formula of polyethylene molecule is (C2H4)n
n = 750
Therefore, Formula of polyethylene molecule is (C2H4)750 = C1500H3000
Molecular weight = (1500×12.1 + 3000×1)g/mol = 18,150 + 3,000 = 21,150 = 21,200g/mol (to three significant figures)