Zn + 2HCI -> ZnCl2 + H2 a. How many moles of ZnCl, can be made from 1.7g of Zn?

b. If 6.4 grams of HCl are used in this reaction, how many moles of ZnCl, are
produced?

0.02740 moles ZnCl2

0.8777 moles ZnCl2

Explanation:

a) How many moles of ZnCl, can be made from 1.7g of Zn?

First we need to convert from grams of Zn to moles of Zn, and then from moles of Zn to moles of ZnCl.

We will use the atomic weight of Zn to do this..

Atomic weight is 65.38 g Zn/1 mol Zn, this can also be written as

1 mol Zn/65.38mol Zn... We will now convert:

1.76 g Zn *   = 0.0273784032 moles Zn

Now we'll use the balanced chemical equation to convert from moles of Zn to moles of ZnCl..

Zn + 2HCl -> ZnCl2 + H2

We can see that for every mol of Zn that reacts, 1 mol of ZnCl2 is produced..

So:

0.0273784032 moles Zn * = 0.0273784032 moles ZnCl2

This can be estimated to 0.0274 moles ZnCl2

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b) If 6.4 grams of HCl are used in this reaction, how many moles of ZnCl, are

produced?

First we need to convert form grams of HCl to moles of HCl, and then to moles of ZnCl...

We'll do this using the atomic weight of HCl (36.458 g/mol or 1 mol/36.458 g)

6.4 g HCl * = 0.1755444621 mol HCl

Now we'll use the balanced chemical equation to convert from moles of HCl to moles of ZnCl..

Zn + 2HCl -> ZnCl2 + H2

We can see that for every 2 moles of HCl that react, 1 mol of ZnCl2 is produced..

So:

0.1755444621 mol HCl * = 0.877722311 moles ZnCl2 are produced.

This can be estimated to 0.8777 moles ZnCl2

1. they vary with a higher number because boiling is way hotter than melting

i do not get it   at all