Introduction to Thermochemistry

Thermal energy always moves:

• From a high temperature object to a lower temperature object.

• From a lower temperature object to a higher temperature object.

• From an object with lower kinetic energy to an object with higher kinetic energy.

• From an object of higher mass to an object of lower mass.

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The second  law of thermodynamics states that entropy of a system  tends to ______________. 

• increase

• decrease

• stay constant

• fluctuate wildly

The temperature of a glass of cold water will eventually...

• Match the temperature of the surrounding environment.

• Always be colder than the surrounding environment.

• Become warmer than the surrounding environment.

• Never change temperature.

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The first law of thermodynamics states that energy is

• created

• destroyed

• conserved

• created and destroyed

H₂ + 2 C + N₂ + 270.3 kJ --> 2 HCN
Is this reaction endothermic or exothermic?

• Endothermic 

• Exothermic

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Enthalpy is energy absorbed or relased during a chemical reaction as

• light.

• heat.

• sound.

• pressure.

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A reaction is performed in a beaker with a temperature probe recording the temperature changes of the reaction.  If the temperature began at 15.0 degrees Celsius and ended at 27.5 degrees Celsius.  If the reaction is our system, is the system endothermic or exothermic?

• Exothermic

• Endothermic

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The reaction of calcium chloride and water in the hot pack

tindak balas antara kalsium klorida dengan air dalam pek panas

(a)  

• releases water/ membebaskan air

• releases heat/ membebaskan haba

• absorbs water/ menyerap air

• absorbs heat/ menyerap haba

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Diagram shows reaction between sodium and water. The reaction is

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Cake baking is

• endothermic

• exothermic

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