I am still having trouble with this question It says What is the molarity of a solution containing 18.0g of KCl in 262mL of KCl solution? When I calculated it I got .92154 m. I had changed 18 g into moles and 262 ml into liters and then divided the moles into liters. I was wondering where I went wrong because that isn't the answer in the book.
The correct answer is 0.92154 using 74.551 for the molar mass of KCl. Rounded to 3 s.f. that is 0.922 and note that is M and not m. M stands for molarity, m stands for molality.
What's the answer in the book?
To find the molarity of a solution, you need to divide the number of moles of solute by the volume of the solution in liters. It seems like you followed the correct steps for converting grams to moles and milliliters to liters. However, there might be an error in one of your calculations or conversions.
Let's go through the calculations step by step to find the mistake:
1. Convert 18.0 grams of KCl into moles:
- The molar mass of KCl is 74.5513 g/mol (39.10 g/mol for K + 35.45 g/mol for Cl).
- Divide 18.0 g by the molar mass (18.0 g / 74.5513 g/mol) = 0.2416 moles.
2. Convert 262 mL of KCl solution into liters:
- There are 1000 mL in a liter, so divide 262 mL by 1000 to get 0.262 liters.
3. Calculate the molarity by dividing moles by liters:
- Molarity (M) = moles of solute / liters of solution
- M = 0.2416 moles / 0.262 liters = 0.923 molarity (rounded to 3 decimal places).
Based on these calculations, it seems like the molarity of the solution should be 0.923 M, not 0.92154 M. Please double-check your calculations to find the discrepancy. Additionally, make sure to consider significant figures when reporting your final answer.