# Chemistry honors Essay

This report discusses an experiment to find out the type of metal a coin is made out of by calculating it’s density. It is made to gather an understanding and comparing of a triple-beam balance and a digital electronic balance. It is to test the precision of our measurements. This report presents the procedures for the experiment, the experiment’s results, and an analysis of those results. The materials we used for this experiment was, 30 pre- 1982 pennies and 30 post-1982 pennies. We also used a triple- beam balance and a digital balance.

Last but not least we used, water, a graduate cylinder, small-scale pipette, and cups. The experiment was conducted as follows, after gathering all the required materials, the first part was to weigh 10 pennies, post-1982, on the triple-beam balance, record the mass, and repeat this step with the other 2 piles of 10 pennies. Then weigh the same coins on a digital electronic balance and record the mass. After you’ve done that, fill a graduate cylinder half way with water. Record the volume as accurately as possible. Drop the 10 pennies in the graduate cylinder.

Record the new volume. Dry the pennies as well as you can with paper towels. Subtract step 3 from step 4 to find the volume of pennies. Divide the mass by the volume to find the density of the pennies. (Find the average/ 3 trials). Repeat the experiment with pre-1982 pennies. Compare your results with the rest of the class. For the second part you must measure the mass of an empty cup. Add 50 drops of water from a small-scale pipette to the cup and measure its mass again. Subtract the mass of the empty cup from the mass of the cup with water in it.

To determine the average mass in grams of a single drop, divide the mass of the water by the number of drops (50). The data gathered is quite a lot. For the first trial for mass of the pre-1982 pennies, it weighed 30. G/ml, for the second trial, the pennies weighed 30. G/ml, and for the third trial the pennies weighed in at 30. G/ml. As for the post-1982 pennies for the first trial they weighed 24. G/ml, for the second trial the weighed 24. G/ml, and for the third trial they weighed 24. G/ml, both weighed on a triple beam-balance.

With the digital scale the pre-1982 pennies weighed 7. Egg/ml on the first trial. For the second trial the mass was 10. G/ml, and for the third trial the mass was 9. Egg/ml. For the post-1982 pennies, there was only one trial performed and the mass of it was 6. Egg/ml. The volume of the pre-1982 pennies for the first trial was 4 grams. For the second trial, the volume was 3 grams, and for the third trial the volume was 3. 7 g/ml. As for the post-1982 pennies the volume of the first trial was 3. 9 g/ml, the second trial was 4 g/ l, and the third trial was 3. G/ml. The density for the pre-1982 pennies was 7. 25 g/ml for the first trial. For the second trial the density was 9. Egg/ml, and the third trial was 7. Egg/ml. For the post-1982 pennies, the first trial’s density was 7. 41 g/ml, the second trial was 7. Egg/ml, and the third trial was 8. Egg/ml. Besides the pennies, there was also an empty cup’s mass being weighed and the mass of that cup is 9. G. With 50 drops of water in the cup, the mass of the cup is 10. G. This section analyses the results to the experiment.

The experiment went as expected Witt no unusual events that would have introduced error. The density results of the two piles of pennies Pre-1982 and Post-1982, were 7. G. Ml/egg/ml. Densities of some metals in g/CM Aluminum 2. 70 Lead 11 . 35 Magnesium 1. 74 Cooper 8. 96 Iron 7. 87 Zinc 7. 13 The predominant metal in the pre-1982 pile of pennies was Iron and for the post-1982 pennies the predominant metal was Zinc. Between the two types of balance’s I believe the digital is more accurate because it gives a more precise number.

The average mass of a single drop of water in milliards is 0. Egg. The density of water is 1. Egg/cam. With the calculation of the volume of a single drop in cam and ml (1 ml=CACM) the volume of a drop in micrometers is 0. Mall. The density of water in units of MGM/cam and MGM/ml is ml. Overall the experiment succeeded in finding out the type of metal a coin is made out of by calculating it’s density, gathering an understanding and comparing of a triple-beam balance and a digital electronic balance, and testing the precision of our measurements.