Chem Review

What is calorimetry? Select two that apply.

Calorimetry measures reactions within an insulated device called a calorimeter. Calorimetry is the measurement of heat change in chemical and physical processes.

What is true about entropy?

Entropy is the measure of the degree of randomness and disorder in a system.

Which are true about free energy? Select all that apply.

Free energy indicates whether a reaction will occur spontaneously or not. Free energy is a measure of the energy in a system that is available to do work.

What is true about reaction spontaneity and enthalpy?

Reactions with negative reaction enthalpies are often spontaneous.

Study the reactions. C (s)+O2 (g)→CO2 (g)ΔH=−393.5 kJC (s)+O2 (g)→CO2 (g)ΔH=−393.5 kJ H2 (g)+12O2 (g)→H2O (l)ΔH=−285.8 kJ/molH2 (g)+12O2 (g)→H2O (l)ΔH=−285.8 kJ/mol C (s)+H2 (g)+32O2 (g)→CO2 (g)+H2O (l)ΔH= ?C (s)+H2 (g)+32O2 (g)→CO2 (g)+H2O (l)ΔH= ? Which steps can be used to calculate the enthalpy of Reaction III correctly?

adding the enthalpy of Reaction I and the enthalpy of Reaction II

What is the enthalpy of combustion?

the enthalpy change that occurs when one mole of a substance completely reacts with oxygen

What is the enthalpy of formation?

the overall enthalpy change that occurs when one mole of substance is formed from its elements

Study the reactions. C (s)+O2 (g)→CO2 (g)ΔH=−394 kJC (s)+O2 (g)→CO2 (g)ΔH=−394 kJ H2 (g)+12O2 (g)→H2O (l)ΔH=−286 kJ H2 (g)+12O2 (g)→H2O (l)ΔH=−286 kJ C3H8 (g)+5O2 (g)→3CO2 (g)+4H2O (l)ΔH=−2220 kJC3H8 (g)+5O2 (g)→3CO2 (g)+4H2O (l)ΔH=−2220 kJ 3C (s)+4H2 (g)→C3H8 (g)ΔHf= ?3C (s)+4H2 (g)→C3H8 (g)ΔHf= ? What is the enthalpy of formation of C3H8(g) in Reaction 4?

−106 kJ