Question

Calculate the number of moles of solute in 83.93 mL of 0.1735 M K2Cr2O7(aq).

Answer 1

We know that the formula for the molarity is

Molar concentration or molarity is most commonly expressed in units of moles of solute per litre of solution. For use in broader applications, it is defined as amount of solute per unit volume of solution, or per unit volume available to the species, represented by lowercase c:

Here, n is the amount of the solute in moles, N is the number of molecules present in the volume V (in litres), the ratio N/V is the number concentration C, and N_A is theAvogadro constant, approximately 6.022×10²³ mol⁻¹.
Or more simply: 1 molar = 1 M = 1 mole/litre.

So the number of moles of solute = Molarity * Volume in Litre

As given in the question Volume = 83.93 ml = 0.08393 L

and Molarity = 0.1735 M

So  moles of solute of K₂Cr2O₇ = 0.08393 * 0.1735 = 0.01456 moles

Thank you