A polymer contains 50 molecules with molecular mass 5000,100 molecules with molecular mass 10,000 and 50 molecules with molecular mass 15,000 . Calculate number average molecular mass?

Question

Accepted Answer

Correct answer: C. (c) ∵ Number average molecular mass (M_n^- ) = N_1M_1+N_2M_2+N_3M_3N_1+N_2+N_3 where, N_1 , N_2 and N_3 are number of molecules and M_1, M_2 and M_3 are respectively their molecular masses. Given, N_1=50 and M_1=5000 N_2=100 andM_2=10 ,000N_3=50 andM_3=15 ,000 Thus, M_n^-= N_1M_1+N_2M_2+N_3M_3N_1+N_2+N_3 = (50 5000 )+ (100 10 ,000 )+ (50 15 ,000 )50+100+50 = (25 ,0000 )+ (1 ,000 ,000 )+ (75 ,00 ,00 )200M_n^-=10 ,000 Hence, option (c) is the correct answer.

$A polymer contains 50 molecules with molecular mass 5000,100 molecules with molecular mass 10,000 and 50 molecules with molecular mass 15,000 . Calculate number average molecular mass?$

Solution

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