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May 5, 2015

Homework Help: science

Posted by Josh on Saturday, March 17, 2007 at 10:58pm.

How many grams of hydrochloric acid are required to react completely with 4.30g of zinc?

How many molecules of gas will be produced?

1. Write the balanced chemical equation.
Zn + 2HCl ==> ZnCl2 + H2

2. Convert grams Zn to mols.
mols = grams/atomic mass Zn.

3. Using the balanced equation, convert mols Zn to mols HCl.

4. Now convert mols HCl to grams HCl.
grams HCl = mols HCl x molar mass HCl.

Post your work if you get stuck.

Zn=1 Zn=1
H=2 H=2
Cl=2 Cl=2

mols= 4.30/65.4
=.065749235

I dont know what to do next


mol of HCl=73?

1. Write the balanced chemical equation.
Zn + 2HCl ==> ZnCl2 + H2

2. Convert grams Zn to mols.
mols = grams/atomic mass Zn.
You have 4.30/65.4 = 0.0658 mols Zn which is correct.

3. Using the balanced equation, convert mols Zn to mols HCl.
Use the coefficients in the balanced equation to convert mols Zn to mols HCl.
mols HCl = 0.0658 mols Zn x (2 mols HCl/1 mol Zn) =?? mols HCl


4. Now convert mols HCl to grams HCl.
grams HCl = mols HCl x molar mass HCl.

??mols HCl from step 3 x molar mass HCl = xx

post your work if you have trouble.


4.74

what is the answer for questions a and b? or have we gotten there yet?

grams HCl is thre answer for a.
For part b, work through the same problem but this time you want to find mols of H2 gas. When you know mols, remember that 22.4 L is 1 mol of H2 and use that to determine the volume of H2.

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