Br3C6H3(C8H8)n 0.105% Br

Br3C6H3(C8H8)n 0.105% Br

 

 

Polystyrene can be prepared by heating styrene

with tribromobenzoyl peroxide in the absence of air.

A sample prepared by this method

has the empirical formula Br3C6H3(C8H8)n,

where the value of n can vary from sample to sample.

If one sample has 0.105% Br, what is the value of n?

 

---------------------------------------------------

 

Br3C6H3(C8H8)n의 몰질량을 계산하면,

3(79.90) + 6(12) + 3(1) + n[8(12) + 8(1)]

= 314.7 + 104n

 

 

 

% Br = (Br의 전체 질량 / 화합물의 질량) × 100

( 참고: 조성 백분율 https://ywpop.tistory.com/12958 )

 

0.105% = [(3(79.90)) / (314.7 + 104n)] × 100

 

314.7 + 104n = 239.7 / 0.105 × 100

 

104n = (239.7 / 0.105 × 100) – 314.7

 

n = [(239.7 / 0.105 × 100) – 314.7] / 104

= 2192

 

 

 

답: 2192

 

 

 

 

[검산] [(3(79.90)) / (314.7 + 104×2192)] × 100

= 0.105%