4. A 35.0 mL sample of 1.00 M KBr and a 60.0-mL sample of 0.600 M KBr are mixed. The solution is then heated to evaporate water until the total volume is 50.0 mL. What is the molarity of the KBr in the final solution?
To find the molarity of the KBr in the final solution, we need to calculate the moles of KBr in each solution and then add them together. Then, we can divide the total moles of KBr by the total volume of the solution to get the molarity.
Let's first calculate the moles of KBr in the 35.0 mL sample of 1.00 M KBr.
Moles = Molarity × Volume
Moles = 1.00 M × (35.0 mL / 1000 mL/1 L)
Moles = 0.035 mol
Next, let's calculate the moles of KBr in the 60.0 mL sample of 0.600 M KBr.
Moles = Molarity × Volume
Moles = 0.600 M × (60.0 mL / 1000 mL/1 L)
Moles = 0.036 mol
Now, let's find the total moles of KBr in the solution by adding the moles from both samples.
Total moles = 0.035 mol + 0.036 mol
Total moles = 0.071 mol
Finally, we can calculate the molarity of KBr in the final solution by dividing the total moles by the final volume of 50.0 mL.
Molarity = Total moles / Volume
Molarity = 0.071 mol / (50 mL / 1000 mL/1 L)
Molarity = 1.42 M
Therefore, the molarity of the KBr in the final solution is 1.42 M.
mols KBr soln 1 = M x L = ?
mols KBr soln 2 = M x L = ?
final M = total mols KBr/volume in L.