SG/Chem Blog 2

Over the last week in Sustainable Green Chemistry, we did lots of stuff. For most of the week we did lots of particle diagramming of experiments we did last week. We also learned about the problems that using different kinds of measuring tools can pose and significant figures.

Part 1: Particle Diagramming

Last week we did quite a few experiments with mass and change. To list a few, we took the mass of ice before and after it melted , and the mass of a sugar cube before it dissolved. If you want to read more about these experiments, check out last weeks blog post. This week we diagrammed what we think happened. We did this using particle diagrams.

*Unrelated particle diagram example*

While diagramming, we shared our data, we found that in most cases the mass changed very little or not at all. This is because of the Property of Conservation of Mass, this property causes the mass of an object to stay the same through any chemical reaction. The only experiment we did where this did not apply was when we burned steel wool. For some reason it gained mass, I think that it gained mass because of some reaction of the methane we were burning with the steel wool, or a reaction from the iron in the steel and the air, maybe forming iron oxide. I hope that Dr. Finnan will shed some light on this conundrum.

While doing particle diagramming, I found it interesting that sometimes everyone had very similar models but, other times the models were all very different. I think we had some very well educated discussions about our models in class.

Part 2: Significant figures and measurements

Significant figures are the digits that are important in a number, to find the significant figures, you follow a few simple rules, I will list them below:

1) ALL non-zero numbers (1,2,3,4,5,6,7,8,9) are ALWAYS significant.

2) ALL zeroes between non-zero numbers are ALWAYS significant.

3) ALL zeroes which are SIMULTANEOUSLY to the right of the decimal point AND at the end of the number are ALWAYS significant.

4) ALL zeroes which are to the left of a written decimal point are ALWAYS significant.

                              5)ALL exact counts (20 students) have INFINITE significant figures

Significant figures are important because they tell us how to round our numbers, they also help make our numbers more precise. Both of these reasons are very important for science because having accurate data is important. Another step towards having accurate data is having accurate measurements. For example, different scales will measure to a different level of accuracy (1g,1.0g,1.00g etc...). Also when taking measurements you only estimate 1/10 of the smallest marking on the tool.

Conclusion:

In conclusion, the last week has been very eventful in Sustainable Green Chemistry. We did lots of particle diagramming, and measuring. This week has made me really look forward to the next few weeks. 

See you next week! :)

SG/Chem Blog 1

Over the last two weeks we have begun our epic journey into the world of Sustainable Green Chemistry, Exploring the mystery of the Pom-Pom tubes, blowing up cans, and burning steel wool!

Part 1: Pom-Pom Tube

The first project we did was the Pom-Pom tube project, the tubes were made of PVC pipe, there were four holes on each where a string with a Pom-Pom could stick out. We were then showed what it could do, you could pull on one Pom-Pom and move every other Pom-Pom. Now that we knew what it was capable of doing, it was time to try and find out what was inside making it work.

We were given miniature Pom-Pom tubes and tasked to model the inside of the tube on a whiteboard.

*My group working with the Pom-Pom tube*

As we were shown more ways the Pom-Pom tube could move, our models gradually became more complex. Eventually most of the models ended up like this:

*Suspected Pom-Pom tube innards*

But, that was when the rug was pulled out from under us, when the Pom-Pom tube was opened there was nothing! To this day, nobody really knows what goes on inside the Pom-Pom tube.

Part 2: Blowing up Cans

The Second major thing we did was Blow up a can, We filled it with methane and lit it, it slowly burned and eventually there was a loud band as the can flew a little into the air and settle back down safely.

Like the Pom-Pom tube, we were challenged to create a diagram depicting what happened. While everyone sort of knew what had happened, the methane had burned and the released gasses built up enough pressure in the can top pop the top off, then the gasses escaped and air refilled the can. There were many ways that people depicted particles. Some used triangles, circles, and other shapes while others used colors to represent the particles. Here are some examples:

*Two examples of the can explosion diagrams*

Those are just a few examples of how the particles inside the can were shown. While there were many other ways the particles were shown, those are examples of the most common ways to show particles.

Part 3: Burning Steel Wool

The final project we did actually included many stations. All of the stations were about mass and change, for example we mixed two solutions together and saw how the mass changed, and putting salt cubes in water. But by far the most exciting experiment we did was burning steel wool. we pulled apart a part of steel wool and held it over a burner to burn, while most groups found that they lost mass or had the same mass, my group somehow gained mass. I think that this is just a little bit of human error. I think that the steel wool should have kept the same mass.

Conclusion

Those are the three major things that we did over the last two weeks, I am really looking forward to doing more in Sustainable Green Chemistry.