Fri. Apr 3rd, 2020

# Some Fundamental Definitions In The Science of Chemistry – Some SI Units

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Measurements in the science community is extremely important, therefore, many chemists, have to know how to measure, things well, in order to be able to do their jobs.

If we didn’t have the power to measure things, our lives, wouldn’t make whole lot of sense.

I mean imagine, you walking outside with a shirt that is too tight for your body, or maybe too big, for you.

Many people would look stupid with an outfit, which doesn’t fit, our body, because we didn’t know how to measure, our own body.

## In today’s article, we are going to discuss, some SI (International System) unit quantities, such as: length, volume, mass, density, temperature and time

The meter (m) is the base of length; 1m = 1.094 yd, which shows, that a meter is a little longer then a yard.

Since 1983, the meter has been officially defined as the length of the path travelled by light in a vacuum during a time interval of 1/299,792,458 of a second.

## A centimeter is about two-fifths of an inch, such as: 1cm = 0.3937in; 1in = 2.54cm

Micrometers are used, during biological experiments, when researchers, want to know the size of a cell.

Nanometers, and picometers are used on the atomic size scale and angstrom is the oldest SI unit used today, mainly to express wavelengths and interatomic distances.

Another SI unit that is very powerful today is the volume (V) , which is defined by the amount of space, which any matter occupies.

The cubic meter is the SI unit of volume, which is a metric unit of volume, commonly used in expressing concentrations of a chemical in a volume of air.

The non-SI units, however, are the most important in chemistry, volume units, such as the litter (L) and the milliliter (mL)

## Body fluids are measured, in cubic decimeters (dm3) , by physicians, and other medical practitioners

1L = 1dm3 = 10-3 m3. The prefix milli-indicates that, 1mL is really 1/1000 of a litter, which is also equal to, exactly, 1 cubic centimeter (cm3).

a quart (qt) is slightly less than, a litter is, such that: 1L = 1.057qt and 1qt = 946.4mL.

Something else you may want to know, is that 1ounce of fluids, which is 1/32 of a quart, is equal to 29.57mL.

In a laboratory, there are various types, of glassware, which differ in all types of shapes and have their own measurements.

## The laboratory glassware is designed to contain liquids, and/or measure their volume

If you ever find yourselves, in a laboratory, you will see these types of flasks, a graduated cylinder, a pipet, a beaker, a buret, an Erlenmeyer flask, and a volumetric flask.

You may find others, but these as some of the flasks, which would be available for you to conduct most of your experiments, and measure things the right way.

Some of the flask I just mentioned above are used to contain liquids, and others are used to measure them.

Measurements are very important in the laboratory, because the researcher is able to be less wrong about, their experiments.

In today’s article we couldn’t cover all of the SI units mentioned earlier, but we will continue this conversation in another article.