How many grams of KCl would you need to weigh out to prepare 0.25L of a 2.00 M KCl solution?
How many mols KCl do you need? That'ws M x L = mols.
Then mols KCl = grams KCl/molar mass KCl.
To determine the number of grams of KCl needed to prepare the solution, you will need to use the formula:
Amount of solute (in moles) = concentration (in moles per liter) × volume (in liters)
First, let's calculate the amount of KCl in moles using the given concentration and volume:
Concentration: 2.00 M (moles per liter)
Volume: 0.25 L (liters)
Amount of KCl (in moles) = 2.00 M × 0.25 L
Amount of KCl (in moles) = 0.50 moles
Next, we need to convert moles of KCl to grams. We can utilize the molar mass of KCl to do this:
Molar mass of KCl = atomic mass of K + atomic mass of Cl
Molar mass of KCl = 39.10 g/mol + 35.45 g/mol
Molar mass of KCl = 74.55 g/mol
Finally, we can calculate the number of grams of KCl needed:
Grams of KCl = Amount of KCl (in moles) × Molar mass of KCl
Grams of KCl = 0.50 moles × 74.55 g/mol
Grams of KCl = 37.275 grams
Therefore, you would need to weigh out approximately 37.275 grams of KCl to prepare 0.25 liters of a 2.00 M KCl solution.