Question

How much potassium chloride in grams is needed to prepare 1500ml solution of 3% kcl solution?

This is my answer: 3x1500=4500
4500÷100=45
Answer is 45gm

Answer 1

Is that 3% w/w or 3% w/v. I will assume 3% w/v
3% w/v means 3g KCl in 100 mL solution.
You want 1500 so
3 x 1500/100 = 45 g and you're right.