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Jul 12, 2023 · To identify the basic units of measurement of the seven fundamental properties; Describe the names and abbreviations of the SI base units and the SI decimal prefixes. Define the liter and the metric ton in these units. Explain the meaning and use of unit dimensions; state the dimensions of volume.
- Density and Percent Composition
Units. We know all of density's components, so let's take a...
- Dimensional Analysis
The use of units in a calculation to ensure that we obtain...
- Density and Percent Composition
For example, we usually measure the volume of a liquid sample with pipettes, burets, graduated cylinders, and volumetric flasks (Figure \(\PageIndex{1}\)), whereas we usually measure the mass of a solid or liquid substance with a balance (Figure \(\PageIndex{2}\)).
Learning Objectives. Explain the process of measurement and describe the three basic parts of a quantity. Describe the properties and units of length, mass, volume, density, temperature, and time. Recognize the common unit prefixes and use them to describe the magnitude of a measurement.
- Units of Measure
- The Si Units
- Units Outside The Si
- Units and Their Ranges in Chemistry
Have you ever estimated a distance by stepping it off– that is, by counting the number of steps required to take you a certain distance? Or perhaps you have used the width of your hand, or the distance from your elbow to a fingertip to compare two dimensions. If so, you have engaged in what is probably the first kind of measurement ever undertaken ...
The Base Units of SI
In principle, any physical quantity can be expressed in terms of only seven base units. Each base unit is defined by a standard which is described in the NIST Web site. A few special points about some of these units are worth noting: 1. The base unit of mass is unique in that a decimal prefix (see below) is built-in to it; that is, it is not the gram, as you might expect. 2. The base unit of time is the only one that is not metric. Numerous attempts to make it so have never garnered any succe...
The SI Decimal Prefixes
Owing to the wide range of values that quantities can have, it has long been the practice to employ prefixes such as milli and mega to indicate decimal fractions and multiples of metric units. As part of the SI standard, this system has been extended and formalized.
There is a category of units that are honorarymembers of the SI in the sense that it is acceptable to use them along with the base units defined above. These include such mundane units as the hour, minute, and degree (of angle), etc., but the three shown here are of particular interest to chemistry, and you will need to know them.
In this section, we will look at some of the quantities that are widely encountered in Chemistry, and at the units in which they are commonly expressed. In doing so, we will also consider the actual range of values these quantities can assume, both in nature in general, and also within the subset of nature that chemistry normally addresses. In look...
Every measurement provides three kinds of information: the size or magnitude of the measurement (a number); a standard of comparison for the measurement (a unit); and an indication of the uncertainty of the measurement.
Learning Outcomes. Explain the process of measurement. Identify the three basic parts of a quantity. Describe the properties and base units of length, mass, volume, density, temperature, and time. Memorize base SI unit prefixes. Perform basic unit calculations and conversions in the metric and other unit systems.
People also ask
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Every measurement provides three kinds of information: a number (quantitative observation), a unit (describes how it was measured), and the degree of reliability (uncertainty of the measurement).
