after starting with 0.343g Al and excess HCl the volume of H2 gas collected over water was 472ml. the atmospheric pressure was 754 mmHg and the temp was 21c.
1 balanced chemical equation?
2calculate the pressure in atm of dry hydrogen gas in a mixture
Ptotal = pH2 + pH2O
Ptotal = 754 mm
pH2O = look up the vapor pressure of H2O at 21 C. One web site shows that as 18.7 mm
So 754-18.7 = pH2 which is pressure of the DRY hydrogen gas. Then convert that to atm.
1. The balanced chemical equation for the reaction between aluminum (Al) and hydrochloric acid (HCl) is:
2Al + 6HCl -> 2AlCl3 + 3H2
2. To calculate the pressure of dry hydrogen gas in the mixture, we need to use the ideal gas law equation:
PV = nRT
Where:
P = pressure
V = volume
n = number of moles
R = ideal gas constant (0.0821 L·atm/mol·K)
T = temperature in Kelvin
First, we need to determine the number of moles of hydrogen gas produced. We can use the volume of hydrogen gas collected (472 ml) and convert it to liters:
472 ml = 472/1000 = 0.472 L
Next, we convert the temperature from Celsius to Kelvin:
T(K) = 21°C + 273.15 = 294.15 K
Now we can rearrange the ideal gas law equation to solve for P:
P = nRT/V
We need to find the number of moles of hydrogen gas (n). From the balanced chemical equation, we see that for every 2 moles of aluminum reacted, we get 3 moles of hydrogen gas. Therefore, the number of moles of hydrogen gas produced is:
n = (0.343 g Al) / (26.98 g/mol Al) x (3 mol H2) / (2 mol Al)
n = 0.017583 mol H2
Finally, we can plug in the values into the equation:
P = (0.017583 mol H2) x (0.0821 L·atm/mol·K) x (294.15 K) / (0.472 L)
Calculate P to get the pressure in atm.
1. The balanced chemical equation for the reaction between aluminum (Al) and hydrochloric acid (HCl) is:
2Al + 6HCl → 2AlCl3 + 3H2
2. To calculate the pressure in atm of dry hydrogen gas in a mixture, we need to consider the Dalton's Law of Partial Pressure. According to this law, the total pressure of a mixture of gases is the sum of the partial pressures of each gas. In this case, the partial pressure of hydrogen gas is of interest.
Step 1: Convert the given pressure from mmHg to atm:
Given pressure = 754 mmHg
To convert mmHg to atm, divide the given pressure by 760 mmHg (because 1 atm = 760 mmHg):
Pressure in atm = 754 mmHg / 760 mmHg/atm
Pressure in atm = 0.9934 atm
Step 2: Apply the Dalton's Law and subtract the vapor pressure of water:
The collected hydrogen gas is measured over water, and the vapor pressure of water at the given temperature (21°C) is 18.7 mmHg. We need to subtract this from the total pressure to find the partial pressure of hydrogen gas.
Partial pressure of hydrogen gas = Total pressure - Vapor pressure of water
Partial pressure of hydrogen gas = 0.9934 atm - (18.7 mmHg / 760 mmHg/atm)
Partial pressure of hydrogen gas = 0.9934 atm - 0.0246 atm
Partial pressure of hydrogen gas = 0.9688 atm
So, the pressure in atm of dry hydrogen gas in the mixture is approximately 0.9688 atm.