Zn+HCl---->ZnCl2+H2
If you measure the total volume of collected gas over water at 65*C to be 728 mL at a total pressure of 845 torr, how many milliliters of 2.6 HCl would be required to produce the correct amount of hydrogen?
Is that 2.6M HCl? I will assume so.
Zn + 2HCl ==> ZnCl2 + H2
How many mols H2 is that?
Ptotal = 845 torr
pH2O at 65C = approx 190 torr. You need to look up this value in your text/notes because I've estimated it from some tables I have.
pH2 = 845-190 = about 655 mm or
655/780 = about 0.86 atm
Then use PV = nRT and solve for n = number of mols H2. P is the approx 0.86 (but you use the accurate number), V = 0.728L, T must be in kelvin etc.
Convert mols H2 to mols HCl using the coefficients in the balanced equation. That is ?mols H2 x (2 mols HCl/1 mol H2) = xx.
Then M HCl = mols HCl/L HCl. You have mols and M, solve for L and convert to mL.
To determine the volume of 2.6 M HCl required to produce the correct amount of hydrogen gas, we need to use the given molar ratio between zinc (Zn) and hydrogen gas (H2) in the balanced chemical equation.
The balanced equation is:
Zn + 2HCl → ZnCl2 + H2
From the equation, we see that 1 mole of Zn reacts with 2 moles of HCl to produce 1 mole of H2. This means that the stoichiometric ratio of HCl to H2 is 2:1.
To find the volume of 2.6 M HCl required, we'll follow these steps:
Step 1: Calculate the number of moles of H2.
Since we know the volume of H2 gas collected (given as 728 mL), we can use the ideal gas law equation to find the number of moles.
PV = nRT
Where:
P = total pressure = 845 torr
V = volume of gas = 728 mL
n = number of moles
R = ideal gas constant = 0.0821 L·atm/mol·K (assumed temperature is in Kelvin)
T = temperature = 65°C = 65 + 273 = 338 K
Rearranging the equation to solve for n:
n = PV / RT
Substituting the values:
n = (845 torr * 0.728 L) / (0.0821 L·atm/mol·K * 338 K)
Step 2: Calculate the volume of HCl required.
Since the stoichiometric ratio of HCl to H2 is 2:1, the number of moles of HCl required is half the number of moles of H2.
moles of HCl = moles of H2 / 2
Substituting the value of moles of H2 that we obtained from Step 1:
moles of HCl = (PV / RT) / 2
Step 3: Calculate the volume of 2.6 M HCl required.
Now that we have the moles of HCl required, we can use the molarity (M) and the formula for molarity, which is moles of solute divided by volume of solution in liters, to calculate the volume of 2.6 M HCl:
Volume of 2.6 M HCl = moles of HCl / Molarity of HCl
Substituting the values:
Volume of 2.6 M HCl = [(PV / RT) / 2] / 2.6 M
After performing the calculations, you will get the required volume of 2.6 M HCl in milliliters.