Analytical Chemistry

How to do Dimensional Analysis in Chemistry?

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 Dimensional analysis in Chemistry is often a tricky concept for students to get. Still, it is a significant one and one that you will use throughout all of your chemistry classes.

Dimensional analysis is the process we use to convert a value from one unit or set of units to another. Some important questions to ask yourself when doing a dimensional analysis problem are,

What are the starting units?

What are the units that you wish to obtain?

What are the conversion factors that you can use to get from the starting units to the desired units in the dimensional analysis?

You always use conversion factors to get from one unit or set of units to another.

 Conversion factors are fractions where the numerator and the denominator are an equal quantity expressed in different units because the numerator and the denominator are equal.

You can also express the conversion factor using it is reciprocal, so if one thousand milliliters is equal to one liter you could write that as,

                                                1L/1000 ml


                                                1000 ml/1L

Because those two values are equal the value of the fraction or the conversion factor is one regardless of the direction that the conversion factor.

In some cases, it is crucial to handle dimensions, which are extremely little (like in the dimensions of an atom), or quite large quantities of atoms).   By way of instance, a mass measured in g might be more suitable to utilize if it had been expressed in milligrams (10-3 gram).  Converting between metric units is known as the unit investigation of dimensional analysis.

The unit investigation is a kind of proportional reasoning in which a specified measurement could be multiplied with a known percentage or ratio to provide a result using another unit of measure.  Algebraically, we understand that any amount multiplied by one will probably be unchanged. 

 The specified number is a numerical amount (using its units).  The ratios used are depending upon the units and are put up so that the components in the denominator of this ratio fit exactly the numerator units of the specified and the unit in the numerator of this ratio match those at the following its ratio or the last answer.  Whenever these are multiplied, the specified amount will finally have the right components for the response.

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