A sample of 1.7×10^23 molecules of silicon is moles.

0.28moles of silicon

Explanation:

Given parameters:

Number of molecules of silicon  = 1.7 x 10²³molecules

Unknown:

Number of moles of the silicon  = ?

Solution:

A mole of any substance contains the Avogadro's number of particles.

   1 mole of a substance contains 6.02 x 10²³molecules;

  So;

     1.7 x 10²³molecules contains   = 0.28moles of silicon