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黎曼格新蟲(chóng) (初入文壇)
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[求助]
兩道高化題目。
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1.Styrene is polymerized by free-radical mechanism in solution. The initial monomer and initiator concentrations are 1 M (molar) and 0.001 M, respectively. At the polymerization temperature of 60℃, the initiator efficiency is 0.30. The rate constants at the polymerization temperature are as follows: kd = 1.2×10-5 s-1 kp = 176 M-1s-1 kt = 7.2×107 M-1s-1 Given this information , determine the following: (a) Rate of initiation at 1 min and at 16.6h (b) Steady-state free-radical concentration at 1 min (c) Rate of polymerization at 1 min (d) Average fee-radical lifetime, τ at 1 min, where τ is defined as the radical concentration divided by the rate of termination. (e) Number-average degree of polymerization at 1 min 2.A polymer is fractioned and is found to have the molecular-weight distribution shown below. For this continuous distribution, calculate the following:(a) the number-average;(b)the weight-average;and (c)the z-average molecular weight of the distribution.(分子量是從10^3到10^5) |
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