Exploration – These Guys VS Those Guys #2 – 4/1/14

In class, we have been conducting another set of “These Guys VS Those Guys” experiments. In these, we use the masses of two compounds to determine the amount of gas that is produced in the reaction of the two chemicals. We then use the amount of powder(one of the substances) and the amount of gas to determine the “gas-to-powder” ratio.
In our first test, we used baking powder and vinegar, massing our containers before we added substances, with the substances, and after the reaction.

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We then used our data to determine the mass of the gas produced, and recorded this along with the data from the other groups to make a scatter plot.

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Then, we used our points to find our linear regression, which most of us were close to. However, after using the molecular masses of the compounds to find the best fit line, we determined that there was a huge error in nearly all our calculations, or an error in experimentation. In the end, only three groups(not including ours) had feasible data.

In our second test, we used sodium bicarbonate and vinegar as our substances. We repeated the steps of the first test and recorded all our data.

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We then again used class data to create a scatter plot, and molecular mass to find the best fit line.

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Here, we see much of the data is close or below the line. However, our data(the smile face point) was well above due to spillage of substance during our reaction. We felt this took away the validity of our data.

In our final test, we used baking powder and H2SO4 as our substances. Again, we recorded all data before and after the reaction.

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With class data, we again made a scatter plot,  including our linear regression and the best fit line.

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In this test, nearly all class data is close to or on the best fit line. Our data(the smile face) came rather close to the best fit line, and with no error in calculation, and no known error in the experiment, we felt this data was valid.

In the end, we had gone through these experiments believing we were repeating what we already knew. However, it was revealed to us we were actually doing Stoichiomerty without even knowing! As our lessons lead into Stoichiometry, this is an important thing to know.

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