### 1.5.2. Molar Mass

For fixed composition, variable composition, and reacting mixtures, for which mixture molar mass is governed by the `Ideal Mixture` option, the inverse of the molar mass is computed as a mass-fraction-weighted average of the inverses of the component molar masses:

| (1–35)

You can set a Molar Mass for the mixture in the Material details view instead, if you want.

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