Quantitative Analysis Essay

622 Words 3 Pages
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Analytical chemistry

What is Qualitative Analysis?
Qualitative analysis is the aspect of analytical chemistry dealing with the identification of elements or compounds in an unknown substance. Very simply put, it answers the question "What is in this sample?" and usually does so with yes/no question.

What is Quantitative Analysis?
Quantitative chemical analysis is the aspect of analytical chemistry dealing with determining the quantity of a particular chemical is in a substance. In short, it attempts to answer questions involving "How much?"

Accuracy: Accuracy refers to the agreement between experimental data and a known value. You can think of it in terms of a bull’s eye in which the target is hit close to the
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This distribution shows no tendency toward a particular value (lack of precision) and does not acceptably match the actual temperature (lack of accuracy).

Example of a sensor with GOOD accuracy and BAD precision:
Suppose a lab refrigerator holds a constant temperature of 38.0 F. A temperature sensor is tested 10 times in the refrigerator. The temperatures from the test yield the temperatures of: 37.8, 38.3, 38.1, 38.0, 37.6, 38.2, 38.0, 38.0, 37.4, 38.3. This distribution shows no impressive tendency toward a particular value (lack of precision) but each value does come close to the actual temperature (high accuracy).

Example of a sensor with BAD accuracy and GOOD precision: Suppose a lab refrigerator holds a constant temperature of 38.0 F. A temperature sensor is tested 10 times in the refrigerator. The temperatures from the test yield the temperatures of : 39.2, 39.3, 39.1, 39.0, 39.1, 39.3, 39.2, 39.1, 39.2, 39.2. This distribution does show a tendency toward a particular value (high precision) but every measurement is well off from the actual temperature (low accuracy).

Example of a sensor with GOOD accuracy and GOOD precision: Suppose a lab refrigerator holds a constant temperature of 38.0 F. A temperature sensor is tested 10 times in the refrigerator. The temperatures from the test yield the temperatures of: 38.0, 38.0, 37.8, 38.1, 38.0, 37.9, 38.0, 38.2, 38.0, 37.9. This distribution does show a tendency toward a particular value

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