Final answer:
To find the number of grams of KCl in 250 ml of a 0.28 M KCl solution, first convert the volume to liters and then multiply the concentration by the volume to find the number of moles of KCl. Finally, multiply the moles by the molar mass of KCl to find the mass in grams.
Step-by-step explanation:
To determine the number of grams of KCl in 250 ml of a 0.28 M KCl solution, we can use the equation:
moles = concentration (M) x volume (L)
First, convert the volume from milliliters to liters. Since there are 1000 milliliters in one liter, the volume is 250 ml / 1000 ml/L = 0.25 L.
Next, multiply the concentration (0.28 M) by the volume (0.25 L) to find the moles of KCl:
moles = 0.28 M x 0.25 L = 0.07 moles
To calculate the mass of KCl, we need to know the molar mass of KCl, which is 74.55 g/mol. Multiply the moles of KCl by the molar mass:
mass = moles x molar mass
mass = 0.07 moles x 74.55 g/mol = 5.22 grams of KCl