Question

If anyone can reply to this quickly that would be helpful :-)

The student realizes that the precipitate was not completely dry and claims that as a result, the calculated Na2CO3 molarity is too low. Do you agree with the student's claim?

Answer 1

No

Step-by-step explanation:

Molarity is calculated as:
`(number of moles of solute)/(volume of solution (in liters))`

No of mole of substance is calculated as:
`(mass of substance)/(molar mass of substance)`

From the formula for calculating the number of mole, the more the mass of a substance, the more the number of moles.

Also, from the formula for calculating the molarity of a solution, the more the number of moles, the more the molarity.

Therefore, if the Na2CO3 precipitate was not dry before the mass was taken, it will result in a higher number of mole (more mass due to presence of water) and hence, a higher molarity.

The molarity calculated should have been too high instead of too low.