Mini Mendeleev

State Your Purpose For Doing This Experiment

The experiment was conducted to determine the type ad nature of relationship between the densities of carbon family elements (silicon, lead and tin), and their atomic numbers. This assignment was conducted to confirm the Mendeleev’s periodic law.

Describe The Theory You Are Testing- Mendeleev’s Periodic Law

According to Kotz, Treichel, &, Townsend, (2009), Mendeleev’s periodic law states, "The properties of element are the periodic function of their atomic masses". Mendeleev’s periodic law was premised upon the understanding that elements have varying atomic masses that determine their properties. Therefore, this experiment indicated that different elements of the same family have different atomic masses, and varying volumes.

Summarize And Discuss Your Specific Results

It is clear that the atomic masses are linear between elements of the same group, but the density is not linear across the elements. The atomic masses are linear, but the density is not linear because the elements have atomic that interact differently due to the clustering of the actual atoms.

In consideration of the percentage errors, it is also important to note that the density of the elements were not linear ad probably cannot be used to accurately predict the density of other elements in the same group with 100% precision even if the percentage errors are taken into considerations. Consider the table below.

Name of Element

Density (g/mL)

Average Density (g/mL)

Percent Error (%)

Silicon

2.2 2.3 2.3

2.3

-1.2

Tin

6.2 7.2 7.5

7.0

-5.0

Lead

11.0 11.6 12.2

11.6

2.7

Carbon

Predicted

1.5

-23.1

Germanium

Predicted

5.0

-6.5

Evaluate Your Hypothesis.

The researcher hypothesized that the densities will remain the same for each element, but this hypothesis is wrong, as the densities were different after the experiments. Therefore, it is right to reject or fail to accept the hypothesis.

While it was possible to predict the densities of carbon and germanium, it is important to note the effect of confounding factors such as errors. The percentage errors affect the accuracy of the production. It would be advisable to accept the prediction of values within 10% of the actual values because all chemistry lab experiment has –percentage errors that are acceptable as noted. The density of Carbon was predicted as 1.5 g/mL, with -23.1% errors, while the density of Germanium was predicted as 5.0 g/mL with -6.5 % errors.

Were You Equally Successful In Predicting The Densities Of Carbon And Germanium?

The prediction of germanium was significantly more accurate than that of carbon with germanium having only -6.5% errors, while carbon had -23.1% errors. This large variance in carbon’s prediction was because of thaw nature of carbon. Carbon as an element is not a metal while germanium is a metal. All the other elements under consideration were metals except carbon.

Discuss The Most Significant Source(S) Of Error In This Experiment

There are systematic errors caused by the errors in the calibration of the experiments measuring equipments. Additionally, the incorrect scale reading cased the parallax errors. These errors are called systematic errors and some of the them are not easily controllable.

The other source of errors is the experimenter bias because this causes the absolute and relative errors. For example, the experimental results indicates that there were percentage errors (% Error= -1.2%) that resulted into a 1.2% low prediction. All the element’s measurements had errors. For example, the error in measuring silicon was -1.2, while the error in measuring tin was -5.0, and the measurement error for lead was 2.7.

References

Kotz, J, Treichel, P, &, Townsend, J, (2009). Chemistry and Chemical Reactivity, Volume 2 (7th ed.). Belmont: Thomson Brooks/Cole. p. 324

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