In order to prepare 50.0ml of 0.100M C12H22O11 (sucrose) you will add___grams of C12H22O11 to____ml of water.

Can someone explain how I would solve this? I am lost and do not understand how to do the conversions

1 answer

First, the instructor that made up this problem gets a failing grade. You can not add grams sucrose to ANY amount of water. To make a molar solution you add x grams of the solute to some water, swirl until dissolved, then make to the mark on the volumetric flask. Here is what you do for 50.00 mL of a 0.1 M solution of sucrose.
How many mols of sucrose do you want? That's M x L = 0.100 M x 0.05000 L= 0.005000,
Then grams = mols x molar mass = 0.005000 x approx 342 = ? grams sucrose. You can calculate the molar mass of sucrose more accurately than that and redo the other calculations. To finish, you weigh out the sucrose, place all of it in a 50 mL volumetric flask, add some distilled or deionized water, swirl until all of the sucrose is dissolved, add distilled or deionized water to the mark on the neck of the volumetric flask, mix thoroughly, stopper, label.
The reason you don't want to add the sucrose to the flask, then add 50 mL water is because the volume will now be larger than 50 mL and the M will NOT be 0.100 M.