SOLUTION CONVERSIONS

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1) Percent solution to molarity

M = (% X 10)/Molecular wt.

2) Percent solution to normality

N = (% X 10)/Equivalent wt

3) Molarity to Normality

M = Normality/Valence

4) Normality to Molarity

N = Molarity X Valence

TEMPERATURE CONVERSION

Converting Fahrenheit to Celsius:

Step #1: Correct for the difference in the freezing point of water

Degrees Fahrenheit - 32

Step #2: Correct for the difference in the size of the two temp scales

Multiply by 5/9

(Degrees F are smaller than degrees C)

Therefore:

C = (F - 32) X 5/9

Converting Celsius to Fahrenheit:

Step #1: Correct for the difference in the size of the two temp scales

Multiply by 9/5

(Degrees F are smaller than degrees C)

Step #2: Correct for the difference in the freezing point of water

Add 32

Therefore:

F = 9/5C + 32

HYDRATED SOLUTES

Hydrated solutes should be viewed as "impure" forms of the anhydrous solute with water as the impurity. The "percent assay" of the hydrate can be calculated by dividing the molecular weight of the anhydrous form by the formula weight of the hydrated form. The formula weight of the hydrate can be calculated by adding the molecular weight of the amount of water present to the molecular weight of the pure solute.

EXAMPLE:

MW of CuSO4 is 159.6, MW of water is 18.0. What is the formula weight of CuSO4*5H2O?

5H2O = 5 X 18.0 = 90

159.6 + 90 = 249.6

% Assay = 159.6/249.6 = 63.9%

To determine how many grams of hydrate would be required to provide a specified amount of anhydrous solute, divide the specified amount by the decimal equivalent of the % assay.

EXAMPLE:

How many grams of CuSO4*5H2O are required in order to have 50 grams of CuSO4?

50/0.639 = 78.25

Therefore 78.25g of hydrate are required to provide 50g of pure solute.