The concept of Dimensional Analysis [DA] or Unit Factor Meth…
The concept of Dimensional Analysis [DA] or Unit Factor Method. Using the concept ofDA is fundamental to your success in upcoming chapters. Many calculations in chemistry are combinations of multiplication and division. When to use either can be identified through DA. In DA one uses the dimensions of a value to guide the math operation of multiplication and division. The dimension of a number is the unit such as miles, pound, quart etc. For example, you will be using identities such as 1 kg = 2.2 lbs in making conversions. Chemistry is always making conversions. To convert 10 lbs of apples into bananas we could use the identity of 1 apple = 2 bananas. So the math operation of the identity is to multiply the given [ 10 lbs of apples] by [2] bananas but divide the given by the [ 1 ] apple or in math expression; Xbananas = 10 Ibs apples x 2 bananas/1 apple = 20 lbs of bananas. How does one know to divide the given [10 lbs apples] by apples and not multiply because apples need to cancel [apples/apples = 1] . How does one know to multiply by 2 bananas rather than divide, because the dimension bananas needs to be remaining in the numerator and not the denominator. Now let us see how well you work with this simple concept. Convert 10 inches into centimeters using the identity 1 inch = 2.5 centimeters?
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