6. Compound C (MW = 550) is provided at a concentration of 25g/100mL. 1mL is taken and compound D is to be added (MW = 1025, concentration = 75mM) to give a final ratio of compound C:D of 4:1 moles ratio. What volume of compound D is to be added?
I expect you will never get this answered, at least on this board, until you have determined what kind of ratio you want. Is that 4:1 by grams or by moles?.
by moles
25g C/550 = estimated 0.05 and that dissolved in 100 mL = 0.05/0.1 = about 0.5M.
You take 1 mL of that so you have
0.5 x 0.001L = 5E-4 and that times 4 = about 20E-4.
Then 20E-4/0.075M for D = ?L and convert to mL.
To solve this problem, we need to calculate the number of moles of Compound C and Compound D, and then determine the volume of Compound D needed to achieve the desired 4:1 moles ratio.
First, we need to calculate the number of moles of Compound C. We are given its concentration as 25g/100mL. The molecular weight (MW) of Compound C is 550. To convert grams to moles, we use the formula:
moles = mass (g) / MW
Therefore, the number of moles of Compound C in 1 mL (since we are taking 1mL) is:
moles of C = (25g / 100mL) / 550g/mol
Next, we need to calculate the number of moles of Compound D. We are given its concentration as 75mM, which means 75 millimoles per liter (mMol/L). To convert millimoles to moles, we divide by 1000:
moles of D = (75mMol / 1000) = 0.075 moles/L
Now, we can determine the volume of Compound D needed to achieve the desired 4:1 moles ratio. Since we have already calculated the moles of Compound C in 1 mL (moles of C), we can set up a ratio:
(moles of C) : (moles of D) = 4 : 1
Since we are looking for the volume of Compound D in mL, we need to rearrange the equation and solve for the volume:
volume of D = (moles of D / moles of C) * 1 mL
Plug in the values we have:
volume of D = (0.075 moles / moles of C) * 1 mL
Finally, we substitute the value for moles of C we calculated earlier and solve for the volume of Compound D.