3 questions a little late

Lately we have been flying through material. We have been introduced to the basics of equilibrium, and learned about rates and rate laws!!! In the past few weeks we have learned how EVERYTHING ties together in chemistry. We have also completed a test over the last unit in which we learned about lewis structures, molecular solids, etc. Next I am going to prep for the nerdiest thing I've ever done in my life…..chemical olympics, and also begin reviewing materials we have learned more.

Equilibrium

We began our intro into equilibrium with an explore lab! There were multiple test tubes. Some were in an ice bath, others in water over a hot plate, and some kept at room temperature.

Room Temperature

Hot Plate 

Ice Bath

There was an apparent difference in color in the test tubes, the darkest brown color was in the hot bath while the most colorless was in the ice bath. Each tube had different concentrations but it has the same substances; NO2 and N2O4.

The reaction in this process can be represented by an equation that is both exo and endothermic in that is both a forward and a reverse reaction: 2NO2 ⇌ N2O4

NO2 can be accounted for the brownish orangeish tint of color in the test tubes. It was visible that some test tubes had more of a concentration of NO2 than the rest, for example the test tube in the hot bath. As seen from the picture, it had the deepest brown color. However if one were to move this test tube from the hot bath to the cold bath of water, the test tube would become less colorful. This is because more colorless N204 would be produced. The production of N2O4 is favored by an exothermic process, causing a shift in equilibrium so that homeostasis will be maintained. This causes a faster rate of the forward reaction therefore producing more N2O4.

Now if  a cold tube was placed in a hot bath the effects would then be opposite. The heat would be absorbed therefore making the reaction endothermic and speeding up the rate of a reverse reaction. There would also be the brown/ orange color produced. 

The test tube at room temperature is takin it easy, and has no change in shifts for equilibrium and the rates of the reaction are equal.

This whole explore lab can be explained by LeChatelier's principle in which a system will shift in order to achieve equilibrium.