Enthalpy Change in rate of H of a Reaction - Reaction Enthalpy

The video tutorial explains the concept of reaction enthalpy, its calculation, and its significance in chemical reactions. It covers standard enthalpy and the conditions under which reactions occur, including phase transformations like fusion, vaporization, and sublimation. The tutorial also delves into the standard enthalpy of formation and its application in calculating reaction enthalpy. Finally, it discusses thermochemical equations, emphasizing the importance of stoichiometric coefficients and the extensive nature of enthalpy.

What is the formula for calculating reaction enthalpy?

• Sum of enthalpies of products plus sum of enthalpies of reactants

• Sum of enthalpies of products minus sum of enthalpies of reactants

• Sum of enthalpies of reactants minus sum of enthalpies of products

• Sum of enthalpies of reactants plus sum of enthalpies of products

What does the standard state of a substance refer to?

• Its pure form at 1 atm and any temperature

• Its pure form at 1 bar and any temperature

• Its pure form at 1 bar and 298 Kelvin

• Its pure form at 1 atm and 273 Kelvin

Which of the following is true about the enthalpy of fusion?

• It is always positive

• It is zero

• It is always negative

• It can be either positive or negative

Which process requires heat at constant pressure and a constant boiling temperature?

• Vaporization

• Condensation

• Sublimation

• Fusion

What is the enthalpy change called when a solid directly converts into vapor?

• Enthalpy of condensation

• Enthalpy of fusion

• Enthalpy of vaporization

• Enthalpy of sublimation

What is the standard enthalpy of formation for an element in its standard state?

• It is zero

• It is always negative

• It is always positive

• It can be either positive or negative

What is the standard enthalpy of formation for a compound formed from its elements in their standard states?

• Delta rH theta

• Delta fH theta

• Delta sH theta

• Delta cH theta

How is the enthalpy change of a reaction affected when the reaction is reversed?

• It remains the same

• It is halved

• It changes sign

• It doubles

What is the significance of stoichiometric coefficients in thermochemical equations?

• They refer to the number of molecules

• They refer to the number of moles

• They refer to the number of ions

• They refer to the number of atoms

What happens to the value of delta rH theta when a chemical reaction is balanced differently?

• It doubles

• It becomes zero

• It changes

• It remains unchanged