Enthalpies of Reaction Calculations

Question 1

enthalpy can change for any chemical reaction

Answer 1

heat of reaction

Question 2

enthalpy change for a combustion reaction

Answer 2

heat of combustion

Question 3

heat change when a solid melts (s —> l)

Answer 3

heat of fusion

Question 4

combustion is usually an. . .

Answer 4

exothermic reaction (feels hot to the touch) (delta H is negative)

Question 5

to melt a solid, it takes energy to warm it up so it is an. . .

Answer 5

endothermic reaction (feels cold to the touch) (cold water) (delta H is positive)

Question 6

heat change when a liquid becomes a solid (l —> s)

Answer 6

heat of solidation (delta H is a negative)

Question 7

heat change when a liquid vaporizes (to a gas)

Answer 7

heat of vaporization

Question 8

heat change when a gas condenses to a liquid

Answer 8

heat of consolidation

Question 9

heat required to break a chemical bond

Answer 9

bond dissociation energy

Question 10

heat change when one mole of a substance is formed from its elements

Answer 10

heat of formation

Question 11

heat change when solute dissolves in solvent

Answer 11

heat of solution

Question 12

AgNO3(aq) + HCl(aq) → AgCl(s) + HNO3(aq); delta H= -68kJ

Answer 12

heat of reaction

Question 13

CH4(g) + 2O2(g) → CO2(g) + H2O(g); delta H= -802kJ

Answer 13

heat of combustion

Question 14

H2O(s) → H2O(l); delta H= +6.0kJ

Answer 14

heat of fusion

Question 15

H2O(l) → H2O(g); delta H= +44kJ

Answer 15

heat of vaporization

Question 16

H2(g) → H(g) + H(g); delta H= +436kJ

Answer 16

bond dissociation energy

Question 17

H2(g) + ½ O2(g) → H2O(l); delta H= -285.83kJ

Answer 17

heat of formation

Question 18

LiCl(s) → Li+(aq) + Cl-(aq); delta H= -37.4kJ

Answer 18

heat of solution