Given the following chemical reaction:
Zn+HCl-->ZnCl2+H2(g)
If you measured the total volume of collected gas over water at 20 degrees celcius t be 428ml at a total pressure of 845 torr, how many milliliters of 2.6M HCl would be required to produce the correct amount of Hydrogen?
Use PV = nRT to calculate moles H2 released.
First, look up vapor pressure H2O at 20 C. It's approximately 20 mm.
P = 845-vapor pressure H2O @ 20C and convert that number to atmospheres by dividing by 760.
V = 428 mL, convert to L.
n is what you want to know.
R is 0.08206
T is 20 C converted to Kelvin.
Now that you know moles H2, use the coefficients in the balanced equation to convert moles H2 to moles HCl. Finally, M = mols/L. You know moles HCl and M HCl, solve for L and convert to mL.
To determine the volume of 2.6M HCl required to produce the correct amount of Hydrogen gas, we need to use the stoichiometry of the reaction and the provided conditions.
In the balanced chemical equation: Zn + 2HCl --> ZnCl2 + H2, we see that one mole of Zn reacts with two moles of HCl to produce one mole of H2.
First, we need to calculate the number of moles of H2 using the ideal gas law equation:
PV = nRT
Given:
- Total pressure, P = 845 torr
- Temperature, T = 20 degrees Celsius (which needs to be converted to Kelvin)
- Volume, V = 428 ml
Converting Celsius to Kelvin:
T(K) = T(C) + 273.15 = 20 + 273.15 = 293.15 K
Converting volume from milliliters to liters:
V(L) = V(ml) / 1000 = 428 / 1000 = 0.428 L
Substituting the values into the ideal gas law:
(845 torr) * (0.428 L) = n * (0.0821 L atm mol^(-1) K^(-1)) * (293.15 K)
Solving for n (number of moles):
n = (845 * 0.428) / (0.0821 * 293.15) ≈ 0.158 moles of H2
According to the stoichiometry of the reaction, we know that one mole of H2 is produced for every two moles of HCl reacted. Therefore, we need 0.158 moles of H2 * 2 = 0.316 moles of HCl.
Now, let's calculate the volume of 2.6M HCl solution required to have 0.316 moles:
Concentration of HCl = 2.6M
Volume of HCl = moles of HCl / concentration of HCl
Volume of HCl = 0.316 moles / 2.6 mol/L
Volume of HCl ≈ 0.121 L
Finally, we convert the volume of HCl from liters to milliliters:
Volume of HCl ≈ 0.121 L * 1000 = 121 ml
Therefore, approximately 121 milliliters of 2.6M HCl would be required to produce the correct amount of Hydrogen gas.