Question

---- 239, dau coronița​

Answer 1

ms1 = 100g, c1% = 8%

stim ca c% = mdx100/ms

=> md1 = ms1xc1/100 = 8 g Br2 initial

notam cu a = masa de Br reactionata

ms2 = (100-a)g, c2% = 4,16%

=> md2 = ms2xc2/100

md2 = md1-a = 8-a

=> 100(8-a) = (100-a)x4,16

=> a = 384/95,84 = 4 g Br2 reactionat

2,8g          4g

alchena + Br2 --> produs dibromurat

 miu          160

=> miu = 2,8x160/4 = 112 g/mol

alchena = CnH2n

=> 14n = 112 => n = 8, octena

           C  C

            I   I

C-C=C-C-C-C

                I

                H

=> 4,5-dimetil-2-hexena

=> C)