1) Calculate the amount of sodium chloride, NaCL (mol wt 58.44) and potassium chloride; KCL (Mol wt 74.56) needed to prepare 500 ml of 1.25 NaCL/10 mM kcl solution dilutions in water.
125 what NaCl?
To calculate the amount of sodium chloride (NaCl) and potassium chloride (KCl) needed to prepare a 500 ml solution with a concentration of 1.25 M NaCl and 10 mM KCl, you need to consider the following steps:
Step 1: Determine the number of moles of NaCl needed.
Molarity (M) is defined as the number of moles of solute divided by the volume of the solution in liters. In this case, the volume is given in milliliters (ml), so we need to convert it to liters.
500 ml = 500/1000 = 0.5 L
Molarity (M) = moles of solute / volume of solution in liters
Rearranging this equation, we have:
moles of solute = Molarity (M) x Volume of solution (L)
The molar mass of NaCl is 58.44 g/mol, so we can now calculate the moles of NaCl needed:
moles of NaCl = 1.25 M x 0.5 L
Step 2: Determine the mass of NaCl needed.
To calculate the mass of NaCl needed, multiply the moles of NaCl obtained in Step 1 by the molar mass of NaCl:
mass of NaCl = moles of NaCl x molar mass of NaCl
mass of NaCl = (1.25 M x 0.5 L) x 58.44 g/mol
Step 3: Determine the moles of KCl needed.
Similarly, we need to calculate the moles of KCl. Since the concentration is given in mM (millimoles), we don't need to convert the volume.
moles of KCl = concentration (in mM) x volume of solution (in L)
moles of KCl = 10 mM x 0.5 L
Step 4: Determine the mass of KCl needed.
Like in Step 2, we need to multiply the moles of KCl obtained in Step 3 by the molar mass of KCl:
mass of KCl = moles of KCl x molar mass of KCl
mass of KCl = (10 mM x 0.5 L) x 74.56 g/mol
So, these calculations will give you the amount of sodium chloride (NaCl) and potassium chloride (KCl) needed to prepare a 500 ml solution with a concentration of 1.25 M NaCl and 10 mM KCl.