17.2: The Flow of Energy

The measurement of the heat flow into or out of a system for chemical and physical processes.

• Conductivity.

• Calorimetry.

• Molarity.

The insulated device used to measure the absorption or release of heat in chemical or physical processes is called a ..................................

• voltammeter.

• thermometer.

• calorimeter.

The enthalpy (H) of a system accounts for the heat flow of the system at constant pressure

• True

• False

Name this calorimeter.

• constant- volume calorimeters

• constant- pressure calorimeters

The heat absorbed or released by a reaction at constant pressure is the same as the change in enthalpy, symbolized as ∆𝐻 .

• True

• False

The value of ∆𝐻 of a reaction can not be determined by measuring the heat flow of the reaction at constant pressure.

• True

• False

∆𝐻 is positive for an ......................... reaction.

• endothermic

• exothermic

∆𝐻 is negative for an ......................... reaction.

• endothermic

• exothermic

Name this calorimeter.

• constant- volume calorimeters

• constant- pressure calorimeters

When 25 ml of water containing 0.25 mol HCl at 20^oC is mixed with 25 ml of water containing 0.25 mol NaOH at 20^o C in a calorimeter, the temperature of the solution increases to 30^oC.How much heat (in joules) is released by this reaction?

• 2.9 J

• 2.09 J

• 2090 J