1. Find the molar mass of water (H₂O):
* Hydrogen (H) has a molar mass of approximately 1 g/mol.
* Oxygen (O) has a molar mass of approximately 16 g/mol.
* So, the molar mass of water (H₂O) is 2(1 g/mol) + 16 g/mol = 18 g/mol.
2. Calculate the number of moles of water:
* We have 18 grams of water.
* Since 1 mole of water weighs 18 grams, we have 18 grams / 18 g/mol = 1 mole of water.
3. Use Avogadro's number:
* Avogadro's number states that there are 6.022 x 10²³ molecules in one mole of any substance.
* Therefore, in 1 mole of water, there are 6.022 x 10²³ molecules.
Therefore, there are 6.022 x 10²³ molecules of water in 18 grams of water.
