energetics

Question 1

define enthalpy change

Answer 1

the change in heat energy at a constant pressure

Question 2

what are the standard conditions for enthalpy change

Answer 2

-temperature at 298 K
-pressure at 100 kPa

Question 3

define standard enthalpy of combustion

Answer 3

the enthalpy chnage when one mole of a substance is completely burned in oxygen under standard conditions, and all substances in standard states

Question 4

define enthalpy of formation

Answer 4

the enthalpy change when one mole of a compound is formed from its elements under standard conditions, all substances in standard states.

Question 5

what are the seven diatomic atoms

Answer 5

H2 O2 N2 F2 CL2 BR2 I2

Question 6

define Hess’s law

Answer 6

energy cannot be created or destroyed but can be converted from one form into another
the enthalpy change in a reaction is independent of the route taken and depends only on the initial and final states