Fill in: stray, daily, totally, task, wonder, fear, faint, tightly. 1 Gordon held onto his mum's hand tightly as they crossed the road. 2 Use a map or you may stray into the wrong part of town,

RCOOH=CnH2n+1COOH
W(O)=n*Ar(O)*100/Mr(CnH2n+1COOH)   
Mr(CnH2n+1COOH) =14n+1+12+32+1=14n+46  
43,24=2*16*100/14n+46
43,24*(14n+46)=3200
605,36n+1989,04=3200
n=2
C2H5COOH-пропановая кислота