1. Understand the Chemical Reaction

Hydrogen (H₂) reacts with oxygen (O₂) to form water (H₂O):

2H₂ + O₂ → 2H₂O

2. Calculate Moles

* Hydrogen:

- Molar mass of hydrogen (H₂) = 2 g/mol

- Moles of hydrogen = 8 g / 2 g/mol = 4 moles

* Oxygen:

- Molar mass of oxygen (O₂) = 32 g/mol

- Moles of oxygen = 64 g / 32 g/mol = 2 moles

3. Determine the Limiting Reactant

The limiting reactant is the one that gets completely consumed first, limiting the amount of product formed.

* From the balanced equation: 2 moles of hydrogen react with 1 mole of oxygen.

* We have: 4 moles of hydrogen and 2 moles of oxygen.

* This means: Oxygen is the limiting reactant because it will be used up before all the hydrogen is consumed.

4. Calculate Moles of Water Formed

* From the balanced equation: 1 mole of oxygen produces 2 moles of water.

* Since we have 2 moles of oxygen: We will form 2 moles of oxygen * 2 moles of water/mole of oxygen = 4 moles of water.

5. Calculate Mass of Water

* Molar mass of water (H₂O) = 18 g/mol

* Mass of water = 4 moles * 18 g/mol = 72 g

Therefore, the total mass of water formed when 8 grams of hydrogen reacts completely with 64 grams of oxygen is 72 grams.