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Saccharin is a weak organic base with a Kb of 4.8X10^-3. A 0.672-g sample of saccharin dissolved in 30.0mL of water had a pH of 12.34. What is the molar mass of saccharin?
Let's call saccharin BNH2.
pH = 12.34
pOH = 14-12.34 = 1.66
(OH^-) = about 0.022
......BNH2 + H2O ==> BNH3^+ + 2OH^-
I.......x..............0........0
C...-0.011..........0.011...0.022
E.....x-0.011.......0.011...0.022
Kb = 4.8E-3 = (BNH3^+)(OH^-)/(BNH2)
Subtitute the E line into the Kb expression and solve for x = M saccharin.
Then M = mols/L. You have M and L, solve for mols.
Then mols = grams/molar mass.
Amine derivative Weak Bases do not give 1:2 ionization ratios. Balance your equation, then try your problem again.
I did step by step but answer doesn't match any of the choices it gives me
To find the molar mass of saccharin, we need to go through a few steps. Let's break it down.
Step 1: Calculate the concentration of hydroxide ions (OH-) in the solution.
Since we know the pH of the solution, we can use the formula:
pOH = 14 - pH
In this case, pOH = 14 - 12.34 = 1.66
To find the concentration of hydroxide ions (OH-), we can use the formula:
OH- concentration = 10^(-pOH)
OH- concentration = 10^(-1.66)
Step 2: Calculate the concentration of the base (saccharin) in the solution.
The concentration of the base will be equal to the concentration of hydroxide ions because saccharin is a weak base and dissociates to produce OH- ions.
Step 3: Calculate the number of moles of saccharin dissolved in 30.0 mL of water.
To do this, we need to convert the mass of saccharin (0.672 g) to moles. We can use the formula:
Number of moles = Mass (g) / Molar mass (g/mol)
Step 4: Calculate the molar mass of saccharin.
To find the molar mass, we rearrange the formula from Step 3:
Molar mass (g/mol) = Mass (g) / Number of moles
By following these steps and plugging in the provided values, we can find the molar mass of saccharin.