The AHsol for NaF is 82 kJ/mol, and the lattice energy is -923 kJ/mol. If the hydration enthalpy of sodium is 21 kJ/mol more than the hydration enthalpy of fluoride, what are the hydration enthalpies for the sodium and fluoride ions? Use A
Hsol = - Hat+ AH hydr
Osodium: -841 kJ/mol; fluoride: -862 kJ/mol
Osodium: -431 kJ/mol; fluoride: -410 kJ/mol
O sodium: -410 kJ/mol; fluoride: -431 kJ/mol
Osodium: -389 kJ/mol; fluoride: -410 kJ/mol

Agroup of students is studying convection current. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other is in an area with warm air. after 10 minutes, the balloon are released from a height of 1 meter. which of the following to the students most likely observe? a) the warm balloon expands and rises. the cold balloon shrinks and sinks b) the balloon both rise. the cold balloon is larger than the warm balloon c) the cold balloon expands and rises. the warm balloon shrinks and sinks d) the balloon rise at the same rate. both balloons are the same size