Chapter 10

Chemical Energetics

(The failure is the result of disobedience of first parents then teachers and finally of the Almighty Allah)

Definitions

1. Thermodynamics: -The study of conversion and conservation of heat and other forms of energy is called thermodynamics.

2. Thermochemistry: - it deals with the measurement or calculation of heat absorbed or abandoned in chemical reactions.

3. Thermo chemical reactions: - the chemical reactions which are accompanied by energy changes along with the material changes are generally known as thermochemical reactions.

4. Exothermic reactions: -the chemical reactions which are accompanied by the liberations or emission of energy are called exothermic reactions. 5. Endothermic reactions: -the chemical reactions which are accompanied by the absorption of energy are called endothermic reactions.

6. system: -the collection of matter having certain boundaries is called system

7. Surroundings:- the environment of a system or the thing that affect on a system are included in surroundings.

8. Heat of formation: - the change of enthalpy when one gram mole of a substance is formed from its elements

9. Standard heat of formation: -the change of enthalpy when one gram mole of a substance is formed from its elements at 25oC and 1 atm is called standard heat of formation.10. Enthalpy: -the total heat content of a system is called enthalpy..11. Heat of neutralization: - The amount of heat released during the neutralization process when one mole of water is produced by the reaction of acid and base. Multiple Choice Questions

1. Thermochemical reactions involve:

a) material changesb) energy changes

c) both a & b

d) heat changes

2. EXO means:

a) out of or to evolveb) into or to absorb

c) outside

d) heat

3. H negative represents which reaction:

a) thermochemical

b) exothermic

c) endothermic

d) chemical

4. Formation of water from hydrogen and oxygen produces energy:

a) -286 K.J/mole

b) +286 K.J/mole

c) -393 K.J/mole

d) +393 K.J/mole

5. H positive represents neutralization:

a) true

b) false

6. Acid Base reaction is called neutralization reaction:

a) true

b) false

Questions 7 12

Select from the terms below:

A) endothermic reaction B)exothermic reaction

7. photosynthesis

8. respiration

9. decomposition reaction

10. bond formation

11. combustion

12. melting of ice

The Book MCQs13. in an exothermic reaction:

a) heat energy is lost b) heat energy is gained c) both a & b

d) N.O.T

14. In an exothermic reaction:

a) container becomes hot

b) container becomes cold

c) the temperature of container remains same

d) N.O.T

15. During an endothermic reaction:

a) container becomes cold

b) container becomes hot

c) the temperature of container remains same

d) N.O.T Answer Key1C2A3B

4A5B6A

7A8B9A

10B11B12A

13A14A15A