What mass of KCl (MM = 74.55 g/mol) is required to make 750 mL of a 0.275 M solution?

How many mols do you want? That's mols = M x L = ?

Then mols = grams/molar mass. You know molar mass and mols, solve for grams.

i'm still not getting the correct answer

I can't guess what you've done. Post your work and I'll find the error.

My first guess is that you didn't convert 750 mL to 0.750 L.

.20625

That doesn't help. What you posted is your answer. What I need is your WORK. I need to see your work to find your error; however, I think I see what you did (with a little help from my crystal ball).

You followed half of my instructions and quit. You need to look at the second step.
The first step is to find mols and you've done that. mols = M x L = 0.750 x 0.275 = 0.20625.
Now mols = grams/molar mass
You know mols = 0.20625 and you know molar mass is 74.55 (from the problem); solve for grams KCl and you'll have it. Remember to round your answer to three places.

To find the mass of KCl required to make a 0.275 M solution, we need to use the equation:

Molarity (M) = moles of solute / volume of solution (in liters)

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

750 mL = 750 mL / 1000 mL/L = 0.75 L

Now, rearrange the equation to solve for moles of solute:

moles of solute = Molarity × volume of solution

moles of solute = 0.275 M × 0.75 L = 0.20625 mol

Since we know the molar mass of KCl is 74.55 g/mol, we can now calculate the mass:

mass of KCl = moles of solute × molar mass

mass of KCl = 0.20625 mol × 74.55 g/mol = 15.34 g

Therefore, 15.34 grams of KCl is required to make 750 mL of a 0.275 M solution.