What is n, the number of moles of electrons transferred, in the following reaction?

2 MnO4-(aq) + 16 H+(aq) + 10 Cl-(aq) ===> 2 Mn2+(aq) + 5 Cl2(g) + 8 H2O(l).

Mn goes from +7 on the left to +1 on the right(per Mn atom).

Cl goes from -1 on the left to zero on the right (for each Cl atom/ion). That is all but telling you the number for n.

So is n=5 then? (7-1)+(-1-0)?

or (7-1)+(|-1-0|) then n=7?

My choices are 2, 4, 5, 10, 16...

No. Five is not right.

Notice EACH Mn goes from +7 to +2. That is a change of n = 5 FOR each Mn atom. How many Mn atoms undergo that change? Or look at Cl.
EACH Cl^- goes from -1 to 0. You have ten of them undergoing that change (from 10Cl^- to 5Cl2). What is total n?

so n=10 then, right? 2Mn atoms (2*5), and 1*10 for the Cl...?

right.

In a redox reaction, electrons lost must equation electrons gained. Each Mn gains 5 electrons (from +7 to +2) and there are two of them and 2 x 5 = 10 electrons gained.
For Cl, we have 10 Cl^- (at -1 each) going to 5Cl2 (at zero each), which is 10 electrons lost.

To determine the value of n, we need to examine the balanced chemical equation for the reaction and identify the species that undergo a change in their oxidation state.

In this reaction, the species that undergoes an oxidation state change is Cl-. It is reduced from -1 to 0 to form Cl2.

The balanced equation shows that 10 Cl- ions are required to produce 5 Cl2 molecules.

Since each Cl- ion loses one electron during the reaction, the number of moles of electrons transferred (n) is equal to the number of moles of Cl- ions involved in the reaction.

Therefore, n = 10 moles of electrons transferred.