What is the molarity of a solution containing 18.0 g of KCl in 354 mL of solution?
0.680
To calculate the molarity (M) of a solution, you need to know the amount of solute (in moles) and the volume of the solution (in liters).
Step 1: Convert the given mass of KCl to moles.
The molar mass of KCl is 74.55 g/mol.
Number of moles of KCl = Mass / Molar mass
= 18.0 g / 74.55 g/mol
= 0.242 moles
Step 2: Convert the given volume of the solution to liters.
The given volume is 354 mL = 354 mL * (1 L / 1000 mL)
= 0.354 L
Step 3: Calculate the molarity using the formula:
Molarity (M) = Moles / Volume
= 0.242 moles / 0.354 L
= 0.684 M
Therefore, the molarity of the solution containing 18.0 g of KCl in 354 mL of solution is 0.684 M.
To find the molarity (M) of a solution, you need to divide the number of moles of solute by the volume of the solution in liters.
First, calculate the number of moles of solute (KCl):
1. Determine the molar mass of KCl:
- The atomic mass of potassium (K) is approximately 39.1 g/mol.
- The atomic mass of chlorine (Cl) is approximately 35.5 g/mol.
Therefore, the molar mass of KCl is 39.1 g/mol + 35.5 g/mol = 74.6 g/mol.
2. Calculate the number of moles using the formula:
Moles (n) = Mass (m) / Molar mass (M)
Moles (n) = 18.0 g / 74.6 g/mol
Moles (n) ≈ 0.241 mol
Next, convert the volume from milliliters to liters:
- Divide the volume in milliliters by 1000.
- 354 mL / 1000 mL/L = 0.354 L
Finally, calculate the molarity:
Molarity (M) = Moles (n) / Volume (V)
Molarity (M) = 0.241 mol / 0.354 L
Molarity (M) ≈ 0.682 M
Therefore, the molarity of the solution is approximately 0.682 M.
mole weight of KCl = 39.1+39.45 = 78.55
so, you have
18.0/78.55 moles/.354L = .647mole/L or .647M