For a linear polymer molecule, the total chain length l depends on the bond length between chain atoms d, the total number of bonds in the molecule n, and the angle between adjacent backbone chain atoms θ, as follows: l = n d s i n (θ/2) furthermore, the average end-to-end distance for a series of polymer molecules r is equal to: r = d (n)^1/2 for a linear polytetrafluoroethylene determine: a. the number-average molecular weight for l=2000 nm; b. the number-average molecular weight for r=17 nm.

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-

because natural gas is colorless, odorless, and tasteless, distributors add mercaptan (a chemical that smells like sulfur) to give natural gas a distinct unpleasant odor (it smells like rotten eggs). they locate the types of rock that are likely to contain natural gas deposits.