Thermochemistry

+140 kJ

-40 kJ

-140 kJ

+40 kJ

Infer precise activation energies for each step

Assess directly whether products will form without additional data

Predict outcomes based solely on individual bond energies

Calculate net reaction enthalpy by summing formation enthalpies

+200kJ

−40kJ

+40kJ

−200kJ

To increase voltage output irrespective of thermodynamic principles

To identify reactions that maximize energy output while minimizing undesired waste heat

To calibrate instruments without considering energy interactions between chemical species

To create a battery with absolute zero internal resistance

The magnitude of ΔH would double while maintaining its sign (+/-).

The products and reactants would remain unchanged but ΔH would become zero.

None above, as multiplying changes nature of chemical reactions occurring.

The physical states (s,l,g,aq) indicated for substances may switch places.

Increases time needed for decomposition to occur via energetically demanding pathways.

No observable change in kinetics since catalysis affects equilibrium concentrations of final products.

Speeds up decomposition by providing additional pathways requiring less energetic transitions.

Changes the outcome with different substances produced in the presence of platinum.

It can only be determined if the reaction occurs at standard conditions.

It increases with the number of intermediate steps in a reaction.

It is the same whether the reaction occurs in one step or in a series of steps.

It decreases when reactions proceed at higher temperatures.

Heat capacity at constant pressure

Internal energy of a system

Change in enthalpy

Change in entropy

Sum up all ∆H°f(products) and subtract ∆H°f(reactants).

Multiply each ∆H°f(value) by its respective molecular weight before summing them up.

Add together ∆H°f(reactants) first and then add ∆H°f(products).

Calculate an average between ∆H°f(reactants) and ∆H°f(products).

Heat flow is constant between system and surroundings.

No heat flows between system and surroundings in an exothermic reaction.

Heat flows from system to surroundings.

Heat flows from surroundings to system.