[book_luvr]

Zn+CuCl2 -----> Cu+Cl2
How many moles of copper (II) chloride are required to react completely with 4.75 g of zinc metal.

I wrote:
n(CuCl2)= 4.75gZn*1molCuCl2/134.5gCuCl2
But I think it's wrong .

[azmanam]

do your units cancel?  At the end, all the units should cancel except mol CuCl2.  If they dont, what conversion factor can you insert/remove in order to make the extraneous units cancel?

[book_luvr]

Thats the problem my units dont cancel should it be:
4.75gZn*134.5gCuCl2/65.4gZn

[azmanam]

gCuCl2/gZn is not a valid conversion factor.  Do you remember how to convert from one compound to another in a stoichiometry problem?  you can't go grams to grams, but do you remember what you can convert between?

[book_luvr]

Molar ratio? 1:1
or 1mol CuCl2/134.5gCuCl2

[azmanam]

First, and this is relatively minor, but the equation is wrong.  It's Zn +CuCl2 -> Cu + ZnCl2.
Second, the molar ratio is the most important part of a stoichiometry problem.  You must have a correctly balanced equation to complete a stoichiometry problem.  So, you are correct, the 1:1 molar ratio is the conversion factor we need.

So, we are given g Zn.  We need mol CuCl2.  We know the 1:1 ratio is the key conversion factor.  Do you see how to convert g Zn to something with which we can use the 1:1 ratio - and how to get that to mol CuCl2?