# chemistry

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please explain the dimensional analysis, and atomic structure?

The conversion table for metric to English and English to metric?

Dimensional analysis is the procedure for changing from one unit to another. For example, convert 12 inches to centimeters. The conversion step is as follows:
12 inches x factor = ??cm

Now for the factor. Actually, there are two factors. We know there are 2.54 cm in 1 inch. So the factors are
1 in/2.54 cm AND
2.54 cm/1 in.

So all we need to do in a conversion is use the right factor. Everything else is in place. We have a 50-50 chance of getting the right factor by chance; we use a little common sense and we get it right every time.
Back to the original which is
12 inches x factor = ??cm

We want the factor to be arranged so that the unit we don't want to keep (in this case inches) cancels and the unit we want to keep (in this case cm) stays. So we make the factor 2.54 cm/1 in and put that in for the factor.
12 inches x factor = ??cm.
12 inches x (2.54 cm/1 in) = ??

You see inches in the numerator cancels with the in (for inches) in the denominator and that is the unit we want to get rid of. The cm in the numerator stays and that is the one we want to stay because we want the new units in cm. That's all dimensinal analysis is.
As for atomic structure, that is a couple of chapters in a text. We shall be happy to help if you narrow your question a little. Thanks for using Jiskha.