Example: 1% w/v solution is equivalent to 1:100 w/v ratio strength The concentrations of very weak pharmaceutical preparations (usually weight-in-volume) often are expressed in terms of their ratio strengths. (sp gr 1.25) 5 g/ 1.25 = 4 ml 4 % v/vġ1 Ratio Strength Ratio strength is another way of expressing percentage strenght. Percent volume-in-volume (v/v): the number of milliliters of a constituent in 100 mL of solution or liquid preparationĩ Percentage Example how many grams of dextrose are required to prepare 4000 mL of a 5% solution? g mL x mL x = 5 x 4000 / 100 = 200gġ0 Percentage Example: 5 g of glycerin in 100 mL syrup, express it as % v/v. Percentage means rate per hundred Example 12.5% = 12.5 /100, or 0.125Ĩ Percentage Percent weight-in-volume (w/v): the number of grams of a constituent in 100 mL of solution or liquid preparation Percent weight-in-weight (w/w): the number of grams of a constituent in 100 g of solution or preparation. 10 mL of H2O = 10 g (weight)Ĥ Specific Gravity Substance that have specific gravity less than 1 are lighter than water Substance that have specific gravity greater than 1 are heavier than water Example if mL of an oil weighs g, what is the specific gravity of the oil ? Specific gravity of oil = g/ g =ĥ Specific Gravity The following equation may be used to convert the volume of substance or pharmaceutical preparation to its weight: g = mL x sp gr The following equation may be used to convert the weight of substance or pharmaceutical preparation to its volume: mL = g sp grĦ Specific Volume specific volume = 91/107.16 = 0.849Įxample: calculate the specific volume of a syrup, 91 mL of which weighs g g of water measures mL specific volume = 91/ = 0.849 For specific gravity of liquid and solids, water used as standard.

1 lab 4 Density, Specific gravity, Specific volume, and Expressions of concentrationĢ Density Density is mass per unit volume of a substance.Įxample if 10 ml sulfuric acid weighs 18g, its density is? Density = 18(g)/ 10(mL) = 1.8 g/mLģ Specific Gravity Specific gravity: is a ratio, weight of substance / weight of equal volume of standard substance have the same temperature.

Diluting gravity lab answers