The mass of KF in the mixture is 2.14 g.
To determine the mass of KF (potassium fluoride) in the mixture, we can use the given information and the molar masses of LiF and KF.
Given:
- Mass of the mixture = 5.13 g
- Mass of fluoride in the mixture = 2.99 g
1. **Calculate the mass of LiF (lithium fluoride):**
\[ \text{Mass of LiF} = \text{Mass of fluoride in the mixture} \]
\[ \text{Mass of LiF} = 2.99 \, \text{g} \]
2. **Calculate the mass of KF (potassium fluoride):**
\[ \text{Mass of KF} = \text{Total mass of the mixture} - \text{Mass of LiF} \]
\[ \text{Mass of KF} = 5.13 \, \text{g} - 2.99 \, \text{g} \]
\[ \text{Mass of KF} = 2.14 \, \text{g} \]
Therefore, the mass of KF in the mixture is 2.14 g.