We are working on molarity of a solution in my class, and I am a little stumped on how to set the problems up. Here is one question from my homework.
How many grams of NaCl are needed to make 575mL of 1.5 M NaCl solution?
Thank you in advance :)
How many mols do you need? That's M x L = mols NaCl.
Then mols NaCl = grams NaCl/molar mass NaCl. You know mols and molar mass; solve for grams.
To calculate the number of grams of NaCl needed to make a 1.5 M NaCl solution, you can use the formula:
mass = (molarity) x (volume) x (molar mass)
Step 1: Find the molar mass of NaCl
The molar mass of NaCl is the sum of the atomic masses of sodium (Na) and chlorine (Cl). The atomic mass of sodium is 23 g/mol, and chlorine is 35.5 g/mol. Therefore, the molar mass of NaCl is 23 + 35.5 = 58.5 g/mol.
Step 2: Convert the volume of the solution to liters
The volume given is 575 mL. Convert it to liters by dividing by 1000: 575 mL ÷ 1000 = 0.575 L.
Step 3: Substitute the values into the formula
mass = (1.5 M) x (0.575 L) x (58.5 g/mol)
Step 4: Calculate the mass of NaCl
mass = 50.90625 grams (rounded to five decimal places)
Therefore, 50.90625 grams of NaCl are needed to make a 1.5 M NaCl solution with a volume of 575 mL.