To find the total mass of the reactants in the reaction given by the equation:
\[ \text{FeCl}_3 + 3\text{H}_2\text{O} \rightarrow \text{Fe(OH)}_3 + 3\text{HCl} \]
we need to calculate the molar masses of the reactants \( \text{FeCl}_3 \) and \( 3\text{H}_2\text{O} \).
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Calculate the molar mass of \( \text{FeCl}_3 \):
- Mass of iron (Fe) = 56 amu
- Mass of chlorine (Cl) = 35 amu
- Since there are 3 chlorine atoms, the contribution from chlorine is \( 3 \times 35 = 105 \) amu
Total mass of \( \text{FeCl}_3 \): \[ 56 + 105 = 161 \text{ amu} \]
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Calculate the molar mass of \( 3\text{H}_2\text{O} \):
- Mass of hydrogen (H) = 1 amu
- Mass of oxygen (O) = 16 amu
- Each molecule of water \( \text{H}_2\text{O} \) has \( 2 \text{H} + 1 \text{O} = 2 \times 1 + 16 = 18 \) amu
- For 3 water molecules, the contribution is \( 3 \times 18 = 54 \) amu
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Now, add the mass of the reactants together: \[ \text{Total mass of the reactants} = \text{Mass of } \text{FeCl}_3 + \text{Mass of } 3\text{H}_2\text{O} \] \[ = 161 \text{ amu} + 54 \text{ amu} = 215 \text{ amu} \]
Therefore, the total mass of the reactants is 215 amu.