(a) Calculate the standard enthalpy of formation of gaseous diborane (B2H6) using the following thermochemical information:

(b) Pentaborane (B5H9) is another boron hydride. What experiment or experiments would you need to perform to yield the data necessary to calculate the heat of formation of B5H9(l)? Explain by writing out and summing any applicable chemical reactions.

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4B(s) + 302(g)-2B203(s) 2H2(g) + O2(g)-→ 2H2O(1) ΔΙΡー -571.7 kJ B2H6(g) + 3O2(g)-→ B2O3(s) + 3H20(l) Δ}1°ーー2147.5 kJ