In the reaction between aluminum and hydrochloric acid, how many moles of hydrogen gas would be liberated when 3.612E-2 grams of aluminum are treated with excess hydrochloric acid?
Moles of hydrogen gas liberated = mol
The atmospheric pressure was measured to be 0.9666 atm and the room temperature was 25.00oC. At this temperature, the vapor pressure of water is 23.80 torr. What would be the volume of the number of moles of hydrogen just calculated under these conditions? Enter the answer in mL.
Volume of hydrogen gas = mL
The syringe used in this experiment is calibrated to 60 mL. However, there is a 'dead volume' at the needle end of the syringe that is uncalibrated. This volume equals 1.20 mL. Bearing in mind that the syringe is upside down, what would the reading on the syringe be that corresponded to the volume you have just calculated?
Reading on the syringe = mL
Suppose that you have completed this week's experiment and have determined that the molar mass of aluminum is 24.80 g mol-1. What is the percent error of your experimental result?
Percent error of the experimental result = %
To find the moles of hydrogen gas liberated, we first need to balance the chemical equation for the reaction between aluminum and hydrochloric acid:
2Al + 6HCl -> 2AlCl3 + 3H2
From the balanced equation, we can see that for every 2 moles of aluminum consumed, 3 moles of hydrogen gas are produced.
Given that 3.612E-2 grams of aluminum are reacted, we can find the number of moles of aluminum:
Molar mass of aluminum (Al) = 24.80 g/mol
Moles of aluminum = mass of aluminum / molar mass of aluminum
= 3.612E-2 g / 24.80 g/mol
Now we can calculate moles of hydrogen gas liberated:
Moles of hydrogen gas liberated = (moles of aluminum) * (3 moles of H2 / 2 moles of Al)
Next, to calculate the volume of the hydrogen gas under the given conditions, we'll use the ideal gas law:
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 in Kelvin.
First, convert the given atmospheric pressure from atm to torr:
0.9666 atm * 760 torr/atm = 735.496 torr
Also, convert the room temperature from Celsius to Kelvin:
25.00°C + 273.15 = 298.15 K
Now, we can rearrange the ideal gas law equation to solve for V:
V = (nRT) / P
Substitute the values into the equation to find the volume in liters:
Volume of hydrogen gas = (moles of hydrogen gas liberated * 0.0821 L·atm/mol·K * 298.15 K) / 735.496 torr
Now, convert the volume from liters to milliliters by multiplying by 1000:
Volume of hydrogen gas = (Volume of hydrogen gas in liters) * 1000 mL/L
To calculate the reading on the syringe, subtract the uncalibrated volume (1.20 mL) from the volume of hydrogen gas:
Reading on the syringe = (Volume of hydrogen gas) - 1.20 mL
Finally, to find the percent error of the experimental result, use the formula:
Percent error = |(theoretical value - experimental value) / theoretical value| * 100
Substitute the theoretical molar mass of aluminum (24.80 g/mol) and the experimental molar mass of aluminum into the formula to find the percent error.