9.99 The chemical reaction BBr3(g)+BCl3(g)BBr2Cl(g)+BCl2Br(g) , has an enthalpy change very close to zero. Using Lewis structures of the molecules, all of which have a central boron atom, provide a molecular-level description of why H for this reaction might be very small.

Define the following terms: potential energy, kinetic energy, path-dependent function, state function, system, surroundings.

Under what circumstances is the heat of a process equal to the enthalpy change for the process?

• define state functions and explain their importance.

Using a table of average bond enthalpies. Table 6.2 ( Sec. 6-6b), estimate the enthalpy change for the industrial synthesis of methanol by the catalyzed reaction of carbon monoxide with hydrogen.