Question

How many grams of sodium chloride are needed to make a solution of 1.75 moles NaCl per liter if you need to make 0.250 L of solution? (22.99 g NaCl = 1.0 mole NaCl)

A. 8.75 g

B. 4.598 g

C. 0.250 g

D. 39.75 g

Answer 1

To make a 0.250 L solution with a concentration of 1.75 moles NaCl per liter, 25.57 grams of NaCl are required, based on the molarity and the molar mass of NaCl, which is 58.44 g/mol.

Step-by-step explanation:

The question asks to calculate how many grams of sodium chloride (NaCl) are needed to create a 0.250 L solution with a concentration of 1.75 moles per liter. To find the mass of NaCl required, we need to perform a two-step calculation:

1. Calculate the total moles of NaCl required for the volume of the solution by multiplying the molarity (moles per liter) by the volume in liters: 1.75 moles/L × 0.250 L = 0.4375 moles of NaCl.
2. Convert the moles of NaCl to grams using the molar mass of NaCl, which is given as 58.44 g/mol (not 22.99 g/mol as mentioned in the question, which is the atomic mass of Na only): 0.4375 moles × 58.44 g/mol = 25.57 g of NaCl.

None of the options provided (A, B, C, D) matches the calculated value of 25.57 grams, and it appears there might be an error with the molar mass given in the question.