Ben has 1L of 0.1mol/dm3 solution of KI & wish to take a sample containing 8.3g of solute.What volume should he measure
moles KI = grams KI/molar mass
You have g KI and molar mass, solve for moles. Then M = moles/L soln. You know M and moles solve for L (Note: 0.1 mol/dm^3 = 1L)
To find the volume that Ben should measure to obtain 8.3g of solute, we need to use the concentration of the solution to calculate the number of moles of solute present.
First, let's calculate the number of moles of solute in the 1L solution:
Number of moles = concentration × volume
Number of moles = 0.1 mol/dm³ × 1 L
Number of moles = 0.1 mol
Now, we can use the molar mass of KI (potassium iodide) to convert the number of moles into grams:
Molar mass of KI = 39.10 g/mol (potassium) + 126.90 g/mol (iodine)
Molar mass of KI = 166.00 g/mol
Mass = number of moles × molar mass
8.3 g = number of moles × 166.00 g/mol
Rearranging the equation:
Number of moles = 8.3 g / 166.00 g/mol
Number of moles ≈ 0.05 mol
Finally, we can use the equation for the number of moles to find the volume that contains 0.05 mol of solute:
Volume = number of moles / concentration
Volume = 0.05 mol / 0.1 mol/dm³
Volume = 0.5 dm³
Therefore, Ben should measure 0.5 dm³ (or 500 mL) of the solution to obtain 8.3 g of solute.