♦ Formic acid is supplied as a clear colorless liquid. A 95% (w/w) concentrated formic acid can be obtained from different suppliers.
♦ 95% (w/w) formic acid means that 100 g of Formic solution contains 95 g of HCOOH.
♦ The density of 95% (w/w) formic acid is 1.22 g/ml at 25° C which means that the weight of the 1 ml of formic acid is 1.22 grams at 25°C.
♦ Molarity refers to the number of moles of the solute present in 1 liter of solution.
♦ In simple words, 1 mole is equal to the atomic weight of the substance. For example, 1 mole of formic acid is equal to 46.03 grams of HCOOH (molecular weight = 46.03).
Calculation procedure:
| Known values | |
| Density of 95% Formic acid | 1.22 g/ml |
| Molecular weight of HCOOH | 46.03 g/mole |
| Concentration of Formic acid | 95% (% by mass, wt/wt) |
Step 1: Calculate the volume of 100 grams of formic acid.
Formula:
Density = weight / volume or
Volume = weight / density
Volume of 100 g of formic acid: 100/1.22 = 81.967 ml
Note: 95% (w/w) Formic acid means that 100 g of solution contain 95 g of HCOOH.
The volume of 100 grams of formic acid is 81.967 ml. That means 95 grams of HCOOH is present in 81.967 ml of formic acid.
Step 2: Calculate how many grams of HCOOH is present in 1000 ml of Formic acid.
81.967 ml of Formic acid contains = 95 grams of HCOOH
1 ml of Formic acid will contain = 95/81.967 grams of HCOOH
1000 ml of Formic acid will contain = 1000 x 95/81.967 = 1159.003 grams of HCOOH
1000 ml of formic acid will contain 1159.003 grams of HCOOH.
Step 3: Calculate the number of moles of HCOOH present in 1159.003 grams of HCOOH.
46.03 grams of HCOOH is equal to 1 mole.
1 gram of HCOOH will be equal to 1/46.03 moles.
1159.003 grams will be equal to = 1159.003 x 1/46.03 = 25.179 moles
Therefore, we can say that 1 liter of formic acid contains 25.179 moles of HCOOH or in other words molarity of 95% (w/w) Formic acid is equal to 25.179 M.
Calculator – Calculate the molarity of concentrated Formic acid (HCOOH)
Use Calculator to calculate the molarity of concentrated Formic acid (HCOOH) when concentration is given in % by mass (w/w)
Formic acid (HCOOH) Molecular weight: 46.03 g/mol
Concentration of Formic acid in % (wt/wt) : % (wt/wt)
(Change the % (wt/wt) concentration)
Density of glacial Formic acid: g/ml
(Change the density)
Molarity of Formic acid: 25.179 M
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