CH 101 Lecture Notes - Lecture 2: Molar Mass, Dimensional Analysis, Exothermic Process

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scarletbear192

2 Sep 2016

School

University of Alabama

Department

Chemistry

Course

CH 101

Professor

John Mc Duffie

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Document Summary

Units are quantities used to specify measurements, which are critical in chemistry. Two most common unit systems are as follows: Metric system: used in most of the world. Scientists use the international system of units (si) which is based on the metric system. Meter, kilogram, second, kelvin, mole, ampere, candela. Accuracy refers to how lose the measured value is to the actual value. If they are close to the actual value. Precision refers to how close a series of measurements are to one another or how reproducible they are. If they are consistent with one another. Measurements are reported so that every digit is certain with the exception of the last digit, which is estimated. First three digits are certain, last digit is estimate. Error that has equal probability of being too high or too low. Error that tends toward being either too high or too low. Deal with writing numbers to reflect precision.

Related Questions

Experimental outcomes in chemistry depend on making sound observations, taking precise measurements and accurately recording them directly in to the laboratory notebook. All experiments and therefore the results will contain errors (experimental error), which can adversely affect the reliability of the experiment and the credibility of the scientist. Experimental error is reduced when students master experimental techniques and become aware of which measurements have the most impact on the experiment in terms of accuracy and precision. Accuracy is determined by comparing the true or actual value to an individual experimental value or the average of many experimental values. If the true value is not given, the average of all the experimental values is assumed to be true value and accuracy is determined by comparing the average to the individual experimental values. Precision is a determined by comparing how close all the experimental values are to each other. The following data was collected by students in your laboratory section. Decide which value to you will use to complete the experimental calculations. The amount of error in your final experimental result depends on your decision. Each student used a different balance and weighed the beaker 4 times. The balances they used in the laboratory read to a hundredth of a gram. The results are shown below were recorded by each individual. What additional information about the students, instruments, and the conditions which the data was collected do you need to better of the evaluate the reliability of the experimental data? Give 1 and briefly (60 words or less, using complete sentences) explain your answer. Which set of data is the most precise? Show all equations and calculations. Briefly (60 words or less, using complete sentences) explain your answer. What student measurements are the least accurate? Briefly (60 words or less, using complete sentences) suggest how this student could improve their experimental techniques. Show all equation and calculations

CH 101 Lecture Notes - Lecture 2: Molar Mass, Dimensional Analysis, Exothermic Process

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