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Density Measurements from Experimental Data

Please explain and answer:
1) A student performed an experiment to determine the density of neopentyl alcohol with the following results:
Trial 1 Density: 0.815 g/ML
Trial 2 Density: 0.932 g/mL
Trial 3 Density: 0.691 g/mL

(a) Determine the mean and average deviation of these measurements. Are these measurements precise?
(b) Determine the percent error in these results. The accepted value of the density of neopentyl alcohol is 0.812 g/ML. Are these results accurate?

2) A student determined the mass of a liquid sample using 2 different electronic balances. Using balance #1 the liquid sample was determined to have a mas of 15.1 g. Using balance #2 the mass of the liquid sample was determined to be 15.072 g. Are these 2 mass measurements equally precise? If not, which is more precise?

3) If possible, why should repetitive measurements always be made when performing an experiment?

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Solution Preview

Hello! Here is help with your problem.

1a) The mean is also known as the average. It is determined by summing the numbers, then dividing that sum by the number of variables (count) included in that sum. In this case, add your three densities then divide by 3.

The average deviation is is calculated in a similar manner as standard deviation, except here you subtract the median from each data item producing a list of deviations from the ...

Solution Summary

This solution defines and explains mean, average deviation, and percent error. It also discusses precision and accuracy in experiments and suggests methods of achieving greater accuracy.