Hello,
I want to know where to start for this problem. Please just point me in the right direction on how to start to solve this problem. Or at least walk me through one so I can figure out the other values. Thank you!
You grind up 2.205 g of an unknown compound and dissolve it in 250 mL of water. You take 5 mL of this solution and dilute it to a volume of 125 mL. Using a titration, you measure the concentration of the resulting solution to be 1.96*10-3 M. Determine which of the following could be the formula of the compound. Show your work. You will need to work backwards from the measured concentration (using the dilution equation) and remember that the molar mass is equal to the mass of a sample over the number of moles in it.
N2O4 P4O10 C6H12O6 MnO2 UF6
I would do this.
End titration gives you 0.00196 mols/L. That was a volume of 125 mL; therefore, mols in that titrated sample is 0.00196 x 0.125 = 0.000245 mols.
How many grams in that end sample that was titrated. That's
2.205 x (5/250) = 0.0441 g.
Now, molar mass = grams/mols = 0.0441/0.000245 = 180
Which of those compounds listed has a molar mass of 180. I think that's glucose; i.e., C6H12O6 but check me out.