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Download Excel Molar mass / molecular weight calculator (MW) for a chemical formula with letter case correction and multi-section formula

## Interdiction

### Molar Mass

Molar mass some times called molecular weight MW is the mass of a molecule. It calculated as the sum of the atomic masses of each constituent element or group of elements multiplied by the number of it in the molecular formula.
Some formulas are quite simple `CaCO3` but there are complex formulas such as `Co3[Fe(CN)6]2.4NH3.6H2 `and some organic compound is much complex.

### Chemical Formula

is a way of presenting information about the chemical proportions of atoms that make up a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as parentheses

https://en.wikipedia.org/wiki/Chemical_formula

### Empirical formula

In chemistry, the empirical formula of a chemical compound is the simplest positive integer ratio of atoms present in a compound

https://en.wikipedia.org/wiki/Empirical_formula

### Mole in Chemistry

The mole (symbol: mol) is the base unit of amount of substance (“number of substance”) in the International System of Units or System International (SI), defined as exactly 6.022 140 76 × 10^23 particles of entities (atoms, molecules, ions or electrons …)

https://en.wikipedia.org/wiki/Mole_(unit)

## Using the Excel Sheet

Download and open Excel file and edit it as needed. Calculate the sheet.
to calculate a formula in a cell, just type something like this `=MW("CaCO3")`.

 Then Formula. The Molecular Weight. CuSO4 159.6 CaCO3 100.1 Co3[Fe(CN)6]2 . 4NH3 . 6H2O 776.9 2Na2CO3 . 3H2O2 314.0 Na2CO3 . 1.5H2O2 157.0 NaBO2 . H2O2 . 3H2O 153.9

## Program OS Support

Windows 2000, Windows XP, Windows Vista, Windows 7, Windows 8, Windows 8.1, Windows 10

Microsoft Excel

## Categories

• CodeProject::Articles::Enterprise Systems::Office Development::Microsoft Excel

## Keywords

VB,VBA,Office,Excel,molar,mass,molecular,weight,Calculator,Calculating,Calculate,Formula

## Related Article

### Category

Articles::Enterprise Systems::Office Development::Microsoft Excel

### A 1-line description

Excel, Pure VBA Macro: Molecular Weight/Molecular Mass Calculator

### Tags

VB, VBScript, Office, MS-Excel, VBA, Calculator, Excel

### A 1-paragraph abstract for Exel molar mass Calculator

In this article, we will explain how to write a pure Excel VBA macro to calculate Molecular Weight or Molecular Mass Calculator of a chemical formula. We go over how we store elements masses in a normal VBA keyed collection. The calculation is done via pure VB code with no additional reference or library with extremely simple code.

### Calculating Molar Mass

In this article, we will explain how to write a pure Excel VBA macro to calculate Molecular Weight or Molecular Mass Calculator of a chemical formula.

It calculates via pure VB code with no additional reference or library with extremely simple code
I add Error handler and line numbering to simplify debugging the code.

## How It Works

First of all, we store elements masses in a normal VBA keyed collection.

```Private Sub SetAtomicMass()
On Error GoTo ErrorHandler
Rem and so on to
Exit Sub
ErrorHandler:
Debug.Print ("Error in: MMW.SetAtomicMass." & Erl & vbNewLine & Err.Description)
Debug.Assert (False)
Call MsgBox("Error in: MMW.SetAtomicMass." & Erl & vbNewLine & Err.Description)
End Sub```

To calculate mass of NaBO2 . H2O2 . 3H2O, we split it into part, NaBO2 , H2O2 , 3H2O.
We split each part like H2O into groups H2 and O.
Calculate the mass of each group and add them together to get the total mass.

```Parts = Split(GetParts(Formula), ", ")
For Each Part In Parts
PartCount = GetPartCount(Part)
PartSymbol = GetPartSymbol(Part)
PartMass = 0
Groups = Split(GetGroups(PartSymbol), ", ")
For Each Group In Groups
GroupCount = GetGroupCount(Group)
GroupSymbol = GetGroupSymbol(Group)
SymbolMass = GetSymbolMass(GroupSymbol)
If SymbolMass = 0 Then
MolecularWeight = 0
Exit Function
End If
GroupMass = GroupCount * SymbolMass
PartMass = PartMass + GroupMass
Next
PartMass = PartCount * PartMass
Mass = Mass + PartMass
Next
MolecularWeight = Mass```