how many grams of KCI would you need to weigh out to prepare 0.250 L of a 2.00 M KCI solution?

Question

can you please show me step by step on how to get this answer?

Answer 1

Since you are given Molarity and Volume(Liters), you can use the Molarity = moles / volume aka M=mol/L formula to obtain the amount of moles required. From there, you would convert moles into grams of KCl.

So first, substitute the known values into the formula.

M= mol/L
2.00M = mol / 0.250L
mol = 2.00 * 0.250
mol = 0.5 moles of KCl

The molar mass of KCl is 74.6g / mol.

So 0.5 moles * 74.6g / mol (mol will cancel out to give you grams) = 37.3g of KCl

Also remember to put your answer in the correct number of significant figures.

Answer 2

2.00M = 2.00 moles per liter

0.250 liters x 2.00 moles/liter = 0.500 moles

0.500 moles KCl x 74.55 grams/mole = 37.275 grams KCl