Question

What is the molarity of formaldehyde in a solution containing 0.25 grams of formaldehyde per mL?

Answer 1

Answer:

8.33mol/L

Explanation:

First, let us calculate the molar mass of of formaldehyde (CH2O). This is illustrated below:

Molar Mass of CH2O = 12 + (2x1) + 16 = 12 + 2 + 16 = 30g/mol

Mass of CH2O from the question = 0.25g

Number of mole CH2O =?

Number of mole = Mass /Molar Mass

Number of mole of CH2O = 0.25/30 = 8.33x10^-3mole

Now we can calculate the molarity of formaldehyde (CH2O) as follow:

Number of mole of CH2O = 8.33x10^-3mole

Volume = 1mL

Converting 1mL to L, we have:

1000mL = 1L

Therefore 1mL = 1/1000 = 1x10^-3L

Molarity =?

Molarity = mole /Volume

Molarity = 8.33x10^-3mole/1x10^-3L

Molarity = 8.33mol/L

Therefore, the molarity of formaldehyde (CH2O) is 8.33mol/L