How many milliliters of a 0.3 molar HCl
solution are needed to react completely with
8 grams of zinc according to the following
equation?
? HCl + ? Zn → ? ZnCl2 + ? H2
Answer in units of mL
First, you need to balance the equation. Can you do that?
You will need two moles of HCl per mole of zinc.
Ask yourself this question:
How many moles of zinc is 8 grams?
I balanced it and got:
2HCL + Zn ---> ZnCl2 + H2
And then to find moles I did: 8/65.37 and got 0.1124 moles.
But now I'm stuck, what do I do next?
You are doing fine so far.
You need 2*0.1124 = 0.2248 moles of HCl.
One liter of the solution contains 0.3 moles of HCl.
You need a bit less than a liter of the acid solution.
Okay, so would I divide 0.3 by 0.2248? >_> I'm sorry, my chemistry is my weakest subject. :(
No, you need less than a liter.
To find the number of milliliters of a 0.3 molar HCl solution needed to react completely with 8 grams of zinc, we need to use stoichiometry and the balanced chemical equation provided.
The balanced chemical equation is:
2 HCl + Zn → ZnCl2 + H2
From the equation, we can see that 2 moles of HCl react with 1 mole of Zn.
First, let's calculate the number of moles of zinc present in 8 grams of zinc:
Molar mass of Zn = 65.38 g/mol
Moles of Zn = Mass of Zn / Molar mass of Zn
Moles of Zn = 8 g / 65.38 g/mol
Next, since the ratio of HCl to Zn is 2:1, we need twice the number of moles of HCl to react completely with the given moles of Zn. So, multiply the moles of Zn by 2 to get the moles of HCl:
Moles of HCl = 2 * Moles of Zn
Finally, use the definition of molarity to find the volume of the HCl solution:
Molarity (M) = Moles / Volume (L)
0.3 M = Moles of HCl / Volume (L)
To find the volume in milliliters, we need to convert liters to milliliters by multiplying by 1000:
0.3 M = Moles of HCl / (Volume (mL) / 1000)
Now, rearrange the equation to solve for the volume (mL):
Volume (mL) = (Moles of HCl * 1000) / 0.3
Substitute the value of Moles of HCl calculated earlier to get the answer in units of mL.