Working With Energy and Chemical Reactions

¶ … tfinal - tinitial = 32.4oC - 25.5oC = 6.9oC

q = mc-t

= 100 grams X 4.184 JX 6.9oC

goC

W= PdV

The enthalpy in the vessel that has not expanded is higher.

As such, the vessel that has not expanded has a higher temperature.

951.9= kJ/mole Chapter 4

=1039.9 kJ/mole Chapter 4

The potential energy for both Chapter 3 and H. is actually higher than Chapter 4 because of the fact that atoms in a chemical bond are more stable than individually separated atoms. The fact that there is a need to use energy to separate the two atoms in the bond adds to the potential energy of the second choice, the Chapter 3 molecule and a H. atom formed. If that bond would be converted, that energy needed to break the bond could actually then be used to do work.

The one with more kinetic energy is the water molecule moving at 1.81 x 103 mi/h because it has a higher velocity and therefore can do more work, showing how it contains more energy.

c. The iodine gas has a higher potential energy compared to the solid iodine. The connections that link the iodine molecules together are broken when it converts from a solid to gas, thus increasing the potential energy.

d. The NO2 molecule that is formed during the collision of a nitrogen monoxide and oxygen atom has the greater energy because it has some of the absorbed energy generated from the actual collision. This is potential energy.

e. The first set of magnets that are touching have more energy, because the farther the magnets are the weaker the energy pull between them is. Thus, the set of touching magnets have greater potential energy.

f. Due to the fact that both molecules are traveling at the same velocity, they have the same amount of kinetic energy.

49. a. The wooden car builds potential energy as it is pulled up the hill. This energy is then transferred into kinetic energy when the wooden car is released and falls down the steep grade of the hill.

b. After the car begins to fall down the backside at high speed, this is an example of the built up potential energy converting into kinetic energy, as the car increases its velocity and is in motion on its own.

c. The wooden coaster shaking is an example of kinetic energy being transferred from one object to another. As the car releases kinetic energy as it speeds down the hill, it is in constant contact with the rail track. This transfers the kinetic energy onto the track, making the foundation shake.

d. This is an example of a building up of potential energy by kinetic energy being converted into potential energy. Yet, at the same time, there is still residual potential energy that is continuing to convert into kinetic energy from the last hill because the car is at a high speed.

63. a. In the process, the equilibrium shifts to the left and this causes less products to form.