If 50.0 mL of 0.150 M magnesium bromide is combined with 200 mL of 0.110 M sodium bromide what is the molarity of the bromide ion in the resulting solution? (assume volumes are additive)
mols MgBr2 = M x L
mols Br = twice that.
mols NaBr = M x L
mols Br = mols NaBr.
M Br = (total mols Br/total volume in L)
To find the molarity of the bromide ion in the resulting solution, we need to determine the total amount of bromide ions present after the two solutions are combined.
Step 1: Calculate the amount of bromide ions from the magnesium bromide solution.
To do this, multiply the volume of the magnesium bromide solution (50.0 mL) by the molarity (0.150 M) to get the number of moles:
(50.0 mL) x (0.150 mol/L) = 7.50 mmol of bromide ions
Step 2: Calculate the amount of bromide ions from the sodium bromide solution.
Multiply the volume of the sodium bromide solution (200 mL) by the molarity (0.110 M) to get the number of moles:
(200 mL) x (0.110 mol/L) = 22.0 mmol of bromide ions
Step 3: Add the amounts of bromide ions from both solutions.
Adding the amounts of bromide ions from step 1 and step 2, we get:
7.50 mmol + 22.0 mmol = 29.5 mmol of bromide ions
Step 4: Calculate the total volume of the resulting solution.
Since the volumes are additive, sum up the volumes of the two solutions:
50.0 mL + 200 mL = 250 mL
Step 5: Calculate the molarity of the bromide ion in the resulting solution.
Divide the total amount of bromide ions (29.5 mmol) by the total volume of the resulting solution (250 mL) and convert to molarity:
(29.5 mmol) / (250 mL) = 0.118 M
So, the molarity of the bromide ion in the resulting solution is 0.118 M.
To find the molarity of the bromide ion in the resulting solution, we can use the concept of stoichiometry and the relationship between the moles of the solute and the volume of the solution.
1. Convert the given volumes of the solutions to liters:
50.0 mL = 0.0500 L
200 mL = 0.200 L
2. Calculate the moles of magnesium bromide (MgBr2):
Moles of MgBr2 = concentration (M) × volume (L)
Moles of MgBr2 = 0.150 M × 0.0500 L
3. Calculate the moles of sodium bromide (NaBr):
Moles of NaBr = concentration (M) × volume (L)
Moles of NaBr = 0.110 M × 0.200 L
4. Determine the total moles of bromide ions (Br-) in the resulting solution by adding the moles of bromide ions from magnesium bromide and sodium bromide.
Total moles of Br- = moles of MgBr2 + moles of NaBr
5. Calculate the total volume of the resulting solution by adding the volumes of the two solutions.
Total volume of solution = volume of MgBr2 + volume of NaBr
Total volume of solution = 0.0500 L + 0.200 L
6. Finally, calculate the molarity of the bromide ion (Br-) in the resulting solution by dividing the total moles of bromide ions by the total volume of the solution.
Molarity of Br- = (Total moles of Br-) / (Total volume of solution)
By following these steps with the given values, you should be able to find the molarity of the bromide ion in the resulting solution.