The experiment described in the procedure was performed using a sample of Calcium with HCl(aq).
The lab conditions were 25.00°C, and 747.0 torr barometric pressure. 112.7 mg of Calcium (MM: 40.08 g/mol) was reacted with 25.00 mL of 1.25M HCl(aq). 71.560g of water was collected when the reaction was complete, and it required 34.53mL of 0.750M NaOH(aq) to titrate the reaction mixture.
Water at 25.00°C has a density of 0.9970 g/cm3, and a vapor pressure of 23.80 torr.
The value for R is 0.082058 L•atm/mol•K.
How many moles of H2 gas are generated?
I know you use the ideal gas law but im really confused as to what pieces of information I plug in.
To find the number of moles of H2 gas generated, you can use the ideal gas law equation: PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature.
First, let's calculate the volume of H2 gas. The volume is given by the volume of water collected, which is 71.560g. To convert this to liters, we need to divide it by the density of water at 25.00°C, which is 0.9970 g/cm³.
Volume (V) = 71.560g / 0.9970 g/cm³
V ≈ 71.86 cm³ or 0.07186 L
Next, let's find the pressure of the H2 gas. The pressure is given as the barometric pressure, which is 747.0 torr. However, we need to subtract the vapor pressure of water at 25.00°C (23.80 torr) to obtain the partial pressure of H2 gas.
Pressure (P) = Barometric pressure - Vapor pressure
P = 747.0 torr - 23.80 torr
P = 723.20 torr
Now, let's calculate the number of moles of H2 gas using the ideal gas law equation. The given value for R is 0.082058 L•atm/mol•K.
PV = nRT
n = (PV) / (RT)
n = (723.20 torr) * (0.07186 L) / (0.082058 L•atm/mol•K * 298.15 K)
n ≈ 0.179 mol
Therefore, approximately 0.179 moles of H2 gas are generated in the reaction.
To determine the number of moles of H2 gas generated in the reaction, you can use the ideal gas law. The ideal gas law equation is:
PV = nRT
Where:
P = pressure (in atm)
V = volume (in liters)
n = number of moles
R = ideal gas constant (0.082058 L•atm/mol•K)
T = temperature (in Kelvin)
In this case, you have the barometric pressure and the temperature, but you need to calculate the volume of H2 gas and convert it to liters. Here are the steps to calculate the number of moles of H2 gas:
Step 1: Convert the mass of water collected to volume by using its density. The formula is:
Volume = Mass / Density
Given:
Mass of water = 71.560 g
Density of water = 0.9970 g/cm3
Converting the mass to volume:
Volume = 71.560 g / 0.9970 g/cm3
Make sure to convert cm3 to liters since the ideal gas law uses liters as the unit for volume.
Step 2: Convert the volume of H2 gas to moles using the ideal gas law equation. Rearrange the equation to solve for n:
n = (PV) / (RT)
Given:
Pressure (P) = 747.0 torr (convert to atm by dividing by 760 torr/atm)
Volume (V) = Volume of water collected (from Step 1) in liters
R = 0.082058 L•atm/mol•K
Temperature (T) = 25.00°C (convert to Kelvin by adding 273.15)
Substitute the values into the equation and solve for n:
n = (747.0 torr / 760 torr/atm) * (Volume / (0.082058 L•atm/mol•K * (25.00+273.15) K))
Step 3: Calculate moles of H2 gas.
Since the balanced chemical equation is not provided, we cannot directly determine the stoichiometry of the reaction. If the balanced chemical equation is known, you can use the mole ratio between calcium and H2 to determine the moles of H2 generated.