【評論主題】9.已知 請問2B(s)+3H2(g)→B2H6(g)的△H 為何?(A) 36 kJ (B) 465 kJ (C) 930 kJ(D) 72 kJ

【評論內容】

2B(s)+3/2O2(g)→B2O3(s)△H=-2546/2 = -1273 (KJ)B2O3(s) +3H2O(g)→B2H6(g)+3O2(g) △H=2035 (KJ)3H2O(l)→3H2O(g) △H=44*3=132 (KJ)3H2(g)+2/3O2(g)→3H2O(l) △H=-572*(3/2)=-858 (KJ)將上述式子相加得到2B(s)+3H2(g)→B2H6(g) △H = -1273+2035+132-858=36 (KJ)

【評論主題】9.已知 請問2B(s)+3H2(g)→B2H6(g)的△H 為何?(A) 36 kJ (B) 465 kJ (C) 930 kJ(D) 72 kJ

【評論內容】

2B(s)+3/2O2(g)→B2O3(s)△H=-2546/2 = -1273 (KJ)B2O3(s) +3H2O(g)→B2H6(g)+3O2(g) △H=2035 (KJ)3H2O(l)→3H2O(g) △H=44*3=132 (KJ)3H2(g)+2/3O2(g)→3H2O(l) △H=-572*(3/2)=-858 (KJ)將上述式子相加得到2B(s)+3H2(g)→B2H6(g) △H = -1273+2035+132-858=36 (KJ)