HOW TO CALCULATE WEIGHT OF THE COMPOUND ACCORDING TO millimoles

How to make solution of millimoles.

There are 1000 millimoles per mole: 1 mole = 1000 millimoles. Another way of expressing the relationship is 1 moles/ 1000 = 1 millimole.

EXAMPLE

For Ferric Oxide: you need to find the molecular  weight for Ferric Oxide with the chemical formula of Fe₂O₃. Look up the atomic weight of iron and oxygen on the periodic table. The atomic weight of iron is 55.845 and the atomic weight of oxygen is 15.999. Add the weight of each atom in the compound:

Molecular Weight of Fe₂O₃ = 2 x 55.845 + 3 x 15.999 = 111.69 + 47.997 = 159.687

This is the weight in grams of 1 mole of the compound.

Convert the weight of one mole to the weight of one millimole. Based in the metric system, one millimole is the same as one mole divided by 1,000. Therefore, the weight of one millimole is equal to the weight of one mole divided by 1,000. Continuing the example:

1 mole of Fe₂O₃ = 159.687 grams per liter and

1 millimole of Fe₂O₃ = 159.687 / 1000 = 0.159687 grams = 159.687 milligrams/liter.

Continuing the example, assume that you require 15 millimoles of Ferric Oxide, find the number of milligrams of Ferric Oxide you need. Based on the fact that one millimole of Ferric Oxide equals 159.69 mg, multiply the number of millimoles by the weight of one millimole:

(15 x 159.687) = 2,395.305 milligrams Fe₂O₃ required per liter.

EXAMPLE

For Potassium Dihydrogen Orthophosphate: you need to find the molecular  weight for Potassium Dihydrogen Orthophosphate with the chemical formula of KH₂PO₄. Look up the atomic weight of Potassium,Hydrogen,Phosphorus and oxygen on the periodic table. The atomic weight of Potassium is 39.098, atomic weight of Hydrogen is 1.008, atomic weight of Phosphorus  is 30.974 and the atomic weight of oxygen is 15.999. Add the weight of each atom in the compound:

Molecular Weight of KH₂PO₄

1 x 39.098 + 2 x 1.008+  1 x 30.974 +  4 x 15.999  = 136.084

This is the weight in grams of 1 mole of the compound. Convert the weight of one mole to the weight of one millimole. Based in the metric system, one millimole is the same as one mole divided by 1,000. Therefore, the weight of one millimole is equal to the weight of one mole divided by 1,000. Continuing the example:

1 mole of KH₂PO₄ = 136.084 grams per liter. and

1 millimole of KH₂PO₄ = 136.084 / 1000 = 0.136084 grams = 136.084 milligrams per liter.

Continuing the example, assume that you require 50 millimoles of Potassium Dihydrogen Orthophosphate,find the number of milligrams of Potassium Dihydrogen Orthophosphate you need. Based on the fact that one millimole of Potassium Dihydrogen Orthophosphate equals 136.084 mg, multiply the number of millimoles by the weight of one millimole: (50 x 136.084) = 6,804.20 milligrams Potassium Dihydrogen Orthophosphate required per liter.

EXAMPLE

For Sulphuric Acid: you need to find the molecular  weight for Sulphuric Acid with the chemical formula of H₂SO₄. Look up the atomic weight of Hydrogen, Sulphur and oxygen on the periodic table. The atomic weight of Hydrogen is 1.008, atomic weight of Sulphur is 32.06 and the atomic weight of oxygen is 15.999. Add the weight of each atom in the compound:

Molecular Weight of H₂SO₄

2 x 1.008+  1 x 32.06 +  4 x 15.999  = 98.072

This is the weight in grams of 1 mole of the compound. Convert the weight of one mole to the weight of one millimole. Based in the metric system, one millimole is the same as one mole divided by 1,000. Therefore, the weight of one millimole is equal to the weight of one mole divided by 1,000. Continuing the example:

1 mole of H₂SO₄ = 98.072grams per liter and

1 millimole of H₂SO₄ = 98.072/ 1000 = 0.098072 grams = 98.072 milligrams per liter.

Continuing the example, assume that you require 30 millimoles of Sulphuric Acid,  find the number of milligrams of Sulphuric Acid you need. Based on the fact that one millimole of Sulphuric Acid equals 98.072 mg, multiply the number of millimoles by the weight of one millimole: (30 x 98.072) = 2,942.16 milligrams Sulphuric Acid  (approx.100%w/w purity) required.

Required Sulphuric Acid 2942.16 mg x 100

Purity 100.00

= 2942.06 mg per liter.

For safety purpose we convert into milliliters by dividing weight per ml. The weight per ml of Sulphuric Acid is 1.84 g approx. So we can take 1.6 ml approx. per liter.

EXAMPLE

For Hydrochloric Acid: you need to find the molecular  weight for Hydrochloric Acid with the chemical formula of HCl. Look up the atomic weight of Hydrogen and Chlorine on the periodic table. The atomic weight of Hydrogen is 1.008 and the atomic weight of Chlorine is 35.45. Add the weight of each atom in the compound:

Molecular Weight of HCL

1 x 1.008+  1 x 35.45 = 36.458

This is the weight in grams of 1 mole of the compound. Convert the weight of one mole to the weight of one millimole. Based in the metric system, one millimole is the same as one mole divided by 1,000. Therefore, the weight of one millimole is equal to the weight of one mole divided by 1,000. Continuing the example:

1 mole of HCl = 36.458 grams  per liter and

1 millimole of HCl = 36.458 / 1000 = 0.036458  grams = 36.458 milligrams per liter.

Continuing the example, assume that you require 80 millimoles of Hydrochloric Acid , find the number of milligrams of Hydrochloric Acid you need. Based on the fact that one millimole of Hydrochloric Acid equals 36.458 mg, multiply the number of millimoles by the weight of one millimole: (80 x 36.458) = 2,916.64 milligrams Hydrochloric Acid (approx.36.5%w/w purity) required.

Required Hydrochloric Acid 2916.64 mg x 100

Purity 36.5

= 7990.79 mg per liter.

For safety purpose we convert into milliliters by dividing weight per ml. The weight per ml of Hydrochloric Acid is 1.18 g approx. So we can take 6.772 ml approx. per liter.