What is the molarity of formaldehyde in a solution containing 0.25 g of formaldehyde (CH₂O)per mL? A)2.5 M B)25 M C)8.3 M D)83 M E)4.0 M

Question

Quizplus · Accepted Answer

To find the molarity, we need to know the amount of formaldehyde in moles and the volume of the solution in liters.

First, we need to convert the given mass of formaldehyde to moles:

0.25 g CH2O × (1 mol CH2O/30.03 g CH2O) = 0.00833 mol CH2O

Next, we need to assume that the solution has a density of 1 g/mL, which means that 1 mL of the solution has a mass of 1 g. Therefore, the volume of the solution in liters is also 0.25 L.

Finally, we can calculate the molarity:

Molarity = moles of solute/volume of solution
Molarity = 0.00833 mol CH2O/0.25 L = 0.0332 M

Rounding to two significant figures, we get a molarity of 0.033 M or 8.3 M. Therefore, the best choice is C, 8.3 M.

What Is the Molarity of Formaldehyde in a Solution Containing