Question

How many grams of KCl would you need to make 250 ml of a 0.5 M solution?

Answer 1

To make a 0.5 M solution of KCl with a volume of 250 mL, you would need 9.32 grams of KCl.

Step-by-step explanation:

To calculate the number of grams of KCl needed to make a 0.5 M solution, we need to use the formula:

Molarity (M) = moles of solute / volume of solution (L)

Rearranging the formula, we get:

moles of solute = Molarity (M) x volume of solution (L)

First, we need to convert the volume from mL to L:

250 mL = 250/1000 L = 0.25 L

Next, we can substitute the given values into the formula:

moles of KCl = 0.5 M x 0.25 L

Finally, we can calculate the moles of KCl and convert it to grams using its molar mass:

moles of KCl = 0.5 M x 0.25 L = 0.125 moles

1 mole of KCl = 74.55 grams

So, the grams of KCl needed = 0.125 moles x 74.55 grams/mole = 9.32 grams

Answer 2

To prepare 250 ml of a 0.5 M KCl solution, you need 9.32 grams of KCl. This is calculated by multiplying the molarity by the volume in liters and then by the molar mass of KCl.

Step-by-step explanation:

To calculate how many grams of KCl (potassium chloride) you need to make 250 ml of a 0.5 M solution, you need to use the formula:

Molarity (M) = moles of solute/liters of solution.

Firstly, convert the volume from milliliters to liters. Since there are 1000 milliliters in a liter, 250 ml is 0.250 liters.

Using the formula, to find the moles of KCl needed:

Moles of KCl = Molarity (M) × Volume (L) = 0.5 M × 0.250 L = 0.125 moles.

Next, calculate the mass in grams using the molar mass of KCl, which is approximately 74.55 g/mol:

Mass of KCl = Moles × Molar Mass = 0.125 moles × 74.55 g/mol = 9.32 grams.

Therefore, you would need 9.32 grams of KCl to make 250 ml of a 0.5 M solution.