0.200 mol of calcium fluoride, CaF2, is added to 250 cm3 of distilled water which is then made up to a total volume of 1.00 dm3. From this solution, 1.00 cm3 is removed. Calculate the amount (in mol) of fluoride ions, F–, removed from the solution.

Sure, here's how to calculate the amount of fluoride ions removed from the solution:

Step 1: Determine the number of moles of fluoride ions in the original solution. Calcium fluoride (CaF2) dissociates in water to form one calcium ion (Ca2+) and two fluoride ions (F-). Therefore, 0.200 mol of CaF2 will produce 2 * 0.200 = 0.400 mol of F- ions.

Step 2: Calculate the concentration of fluoride ions in the solution. The total volume of the solution is 1.00 dm3. So, the concentration (C) of F- ions is given by the formula C = n/V, where n is the number of moles and V is the volume in dm3. Substituting the given values, we get C = 0.400 mol / 1.00 dm3 = 0.400 mol/dm3.

Step 3: Calculate the number of moles of fluoride ions in the 1.00 cm3 of solution that was removed. First, convert the volume from cm3 to dm3 by dividing by 1000 (since 1 dm3 = 1000 cm3). So, the volume is 1.00 cm3 / 1000 = 0.00100 dm3. Then, use the formula n = C * V to find the number of moles. Substituting the given values, we get n = 0.400 mol/dm3 * 0.00100 dm3 = 0.000400 mol.

So, the amount of fluoride ions removed from the solution is 0.000400 mol.

Sure, here's how you can calculate the amount of fluoride ions removed from the solution:

1. First, we need to find the molar concentration of CaF2 in the solution. The molar concentration (C) is given by the formula C = n/V, where n is the number of moles and V is the volume in dm3.

   In this case, n = 0.200 mol and V = 1.00 dm3, so C = 0.200 mol / 1.00 dm3 = 0.200 mol/dm3.

2. Each formula unit of CaF2 produces two fluoride ions (F-) when it dissolves in water. Therefore, the concentration of F- ions in the solution is twice that of CaF2.

   So, the concentration of F- ions = 2 * 0.200 mol/dm3 = 0.400 mol/dm3.

3. Now, we need to find the amount of F- ions in the 1.00 cm3 of solution that was removed. We can do this by multiplying the volume of the solution removed (in dm3) by the concentration of F- ions.

   First, convert the volume from cm3 to dm3: 1.00 cm3 = 0.00100 dm3.

   Then, multiply this volume by the concentration of F- ions to find the amount of F- ions: 0.00100 dm3 * 0.400 mol/dm3 = 0.000400 mol.

So, the amount of fluoride ions, F-, removed from the solution is 0.000400 mol.