To find the mass of the water, we can use the information given about the total mass of the new mixture.
We know:
- Mass of salt = 5.0 grams
- Mass of iodine = 15.0 grams
- Total mass of the mixture = 225 grams
Let \( m \) be the mass of the water. The equation for the total mass of the mixture can be expressed as:
\[ m + \text{mass of salt} + \text{mass of iodine} = \text{total mass} \]
Substituting the values we have:
\[ m + 5.0 , \text{grams} + 15.0 , \text{grams} = 225 , \text{grams} \]
Combining the known masses:
\[ m + 20.0 , \text{grams} = 225 , \text{grams} \]
To find \( m \), subtract 20.0 grams from both sides:
\[ m = 225 , \text{grams} - 20.0 , \text{grams} \] \[ m = 205 , \text{grams} \]
Therefore, the mass of the water is 205 grams, which corresponds to option B.