A student tried to solve the following problem by selecting the conversion below. What, if anything, did the student do wrong?

Question

How many moles of AgNO3 are needed to produce 6.75 moles of copper (II) nitrate Cu(NO3)2 upon reacting with excess copper (Cu)?

2AgNO3 + Cu --> 2Ag + Cu(NO3)2

Students conversion factor: 6.75 mol Cu(NO3)2 x 1 mol Cu(NO3)2/2 mol AgNO3

Question Options:

The student chose the wrong conversion factor.

The student chose the correct conversion factor, but need to flip it to make units cancel.

The student chose the correct conversion factor, but needs to add a second to finish the problem.

There is nothing wrong the problem is ready to be solved.

Answer 1

6.75 mol Cu(NO3)2 x 1 mol Cu(NO3)2/2 mol AgNO3
The correct conversion factor is
6.75 mols Cu x (2 mols AgNO3/1 mol Cu) = ?