The balanced reaction is

CaCO3 + 2 NaF -> CaF2 + Na2CO3
If you start with 20.0 grams CaCO3, how many moles of CaCO3 do you have?

20.0
2.00
.200
.0200
.0386

If you start with .500 moles of NaF, how many moles of CaF2 will form
.500
1.00
1.50
2.00
0.250

What is the sum of the coefficients (including “1”) of the following reaction?
Sodium sulfate + calcium hydroxide ???

4
5
6
7
9

Predict the precipitate that forms: HCl + AgNO 3 ???
HNO3
HCl
AgNO3
AgCl
no precipitate forms

4 answers

DrWLS answered this for you below, for the first one. We want to see some work for the others. If you can't get started, repost one question at a time, and tell us exactly what you don't understand.
A mixture is easier to separate than a compound because a compound is chemically bounded.
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I answered #2 and #3 at the original post.