Ch 7 Chemistry Class 11 Notes

• Define thermochemistry.
• What is thermochemical equation? Give two examples.
• What are thermochemical reactions? Give their types. 
• What information thermochemical equations convey?
• What is spontaneous process? Give two examples. 
• Define heat and work: Heat is not a property of a system. It is therefore not a state function. It is defined as the quantity of energy that flows across the boundary of a system during a change in its state due to the difference in temperature between the system and the surroundings. Heat evolved or absorbed by the system is represented by a symbol q. The sign of q is positive when heat is absorbed by the system from surroundings and it is negative when heat is absorbed by the surroundings from the system. Work Work is also a form in which energy is transferred from one system to another. It is defined as the product of force and distance i.e. W = F x S Work is measured in Joules in SI units. Work is not a state function. The sign of W is positive when work is done on the system and it is negative when work is done by the system.
• What is the difference between a spontaneous and a non-spontaneous reaction?
• What are endothermic and exothermic reactions? Give examples. 
• Differentiate between endothermic and exothermic reactions. 
• Why heat energy is released in exothermic reactions?
• Define system, surrounding, boundary, state and state function.
• State first law of thermodynamics.
• define enthalpy of a reaction. Give an example: The standard enthalpy of a reaction ΔHo is the enthalpy change which occurs when the certain number of moles of reactants as indicated by the balanced chemical equation, react together completely to give the products under standard conditions, i.e 25 °C (298K) and one atmosphere pressure. All the reactants and products must be in their standard physical states. Its units are kJmol-1 .
• Define enthalpy of atomization. Give an example. 
• Define enthalpy of neutralization. Which instrument is used to measure it?
• The enthalpy of neutralization is merely the heat of formation of one mole of liquid water from its ionic components. Justify.
• Define enthalpy of combustion. Give an example. 
• Define enthalpy of solution. Give an example. 
• Draw a labeled diagram of Bomb Calorimeter. 
• Why it is necessary to mention the physical states of reactants and products in the thermochemical equation?
• Burning of a candle is a spontaneous process. Justify it:  There are two types of spontaneous processes:  Those which start and proceed on their own.  Those which are once started (by giving some energy) then proceed on their own. Burning of candle is the example of second type of reactions which are once started with some amount of energy but afterwards proceed and complete on their own. 
• Differentiate between Law of conservation of energy and Hess’s Law: The law of conservation of energy is a physical law that states energy cannot be created or destroyed but can be changed from one form to another. Hess’s law is defined as if a chemical change takes place by several different routes the overall energy change is the same regardless of the route by which the chemical change occurs, provided the initial and final conditions are the same. 
• Is it true that ∆H and ∆E have the same values for the reaction taking place in solution state?
• Differentiate between Internal energy and enthalpy. 
• Is it true that a non-spontaneous process never happens in the universe? Explain it.
• Draw a complete fully labeled Born-Haber Cycle for the formation of Potassium bromide.