The standard enthalpy of formation of B2O3(s) is -1263.6 kJ/mol. Use this information, and the table of standard enthalpies of formations e
to find the (delta)H°f for one mole of B5H9(1).

(Delta)H = -9036.6 kJ/mol
2 BgH9(1) + 12 O2(g) -->5 B2O3(s) + 9 H2O(1)

If the root word engage means “to connect with something,” what does the word disengage mean in the following sentence? he disengaged the gears by stepping on the clutch pedal.a.added more engine powerb.activated a connection to the pedalc.stalled the engined.released a connection to the pedal

Rocks, as they are compressed, begin forming mountains above the earth's surface when two continental plates converge. the continental crust increases in depth as the mountains grow above. the himalayan mountains formed at a convergent plate boundary in this manner. the rocks are smashed together causing them to due to the intense heat and pressure from the colliding plates and eventually forming rock. a) melt; igneous b) layer; sedimentary c) recrystallize; metamorphic d) melt into the earth's interior; metamorphic

The number to the right of an element's symbol (ex. c-12) identifies the of an isotope.