To find the total mass of the reactants in the given reaction \( \text{FeCl}_3 + 3\text{H}_2\text{O} \), we need to calculate the mass contributions of each reactant using their respective atomic masses.
1. Calculate the mass of FeCl₃ (iron chloride):
- Iron (Fe) = 56 amu
- Chlorine (Cl) = 35 amu
- Since there are 3 Cl atoms in FeCl₃: \[ \text{Mass of FeCl}_3 = 56 + (3 \times 35) = 56 + 105 = 161 \text{ amu} \]
2. Calculate the mass of 3H₂O (water):
- Hydrogen (H) = 1 amu
- Oxygen (O) = 16 amu
- Since there are 2 H atoms and 1 O atom in water: \[ \text{Mass of H}_2\text{O} = (2 \times 1) + 16 = 2 + 16 = 18 \text{ amu} \]
- For 3 water molecules: \[ \text{Mass of } 3 \text{H}_2\text{O} = 3 \times 18 = 54 \text{ amu} \]
3. Calculate the total mass of the reactants: \[ \text{Total mass of reactants} = \text{Mass of FeCl}_3 + \text{Mass of } 3\text{H}_2\text{O} = 161 + 54 = 215 \text{ amu} \]
Thus, the total mass of the reactants is 215 amu.