Here's how to calculate the grams in one mole of steam:

* Steam is water (H₂O)

* Molar mass of water:

* Hydrogen (H) has a molar mass of approximately 1 g/mol.

* Oxygen (O) has a molar mass of approximately 16 g/mol.

* Therefore, the molar mass of water (H₂O) is (2 * 1) + 16 = 18 g/mol.

So, there are 18 grams in one mole of steam (or water).