Question

200 mL of solution is prepared by dissolving 20 g of urea in water. The number of moles of urea present in the solution when it is diluted to 500 mL is​

Answer 1

Explanation:

Among the various options given in question statement the correct option is the last one that 0.33 moles

To justify the answer, we first find the number of moles of urea that we have in actual

Formula for the number of moles of urea  =   Mass of urea / Molar mass of urea  

Number of moles = 20 / 60 = 0.33

Now first this much moles are dissolved in 200ml solution and then further diluted to 500Ml solution. However, in both the case the number of moles of urea in the solution would remain the same

​

Answer 2

Given info : 200 mL of solution is prepared by dissolving 20 g of urea in water.

To find : The number of moles of urea present in the solution when it is diluted to 500 mL is​..

solution : in the process of dilution, the amount of solute remains same. it doesn't change during dilution. so, if you dilute the urea solution from 200 ml to 500  ml. the number of moles of urea will not change. its value will be the same as its initial.

   number of moles of urea = given mass of urea/molecular mass of urea.

                                             = 20g/(60g/mol)

                                             = 0.33

therefore the number of moles of urea present in the solution when it is diluted to 500ml is 0.33 mol.