To find the limiting reagent, you need to compare the stoichiometric ratio between the reactants. In this case, the balanced equation tells us that 1 mole of C2H2 reacts with 2 moles of HF.
1. Determine the number of moles available for each reactant:
- Moles of C2H2 = 2.3 mol
- Moles of HF = 12 mol
2. Calculate the number of moles of C2H2 required to react with HF:
- Moles of C2H2 required = 2 * (moles of HF)
- Moles of C2H2 required = 2 * 12 mol = 24 mol
3. Compare the moles available for C2H2 with the moles required:
- Moles of C2H2 available < Moles of C2H2 required
- 2.3 mol < 24 mol
Since the moles of C2H2 available are less than the moles required, C2H2 is the limiting reagent. This means that all 2.3 mol of C2H2 will be completely consumed in the reaction, and the amount of HF is in excess.
To find the pressure in the flask, you can use the ideal gas law equation:
PV = nRT
Where:
P = pressure (in atmospheres)
V = volume (in liters)
n = moles of gas
R = ideal gas constant (0.0821 L.atm/mol.K)
T = temperature (in Kelvin)
1. Convert the temperature to Kelvin:
- Celsius to Kelvin: T(K) = T(°C) + 273.15
- T(K) = 13°C + 273.15 = 286.15 K
2. Determine the moles of the limiting reagent (C2H2), as it will determine the number of moles of the product and hence the pressure:
- Moles of C2H2 = 2.3 mol
3. Plug the values into the ideal gas law equation:
- PV = nRT
- P * 15.4 L = 2.3 mol * 0.0821 L.atm/mol.K * 286.15 K
4. Solve for P (pressure):
- P = (2.3 mol * 0.0821 L.atm/mol.K * 286.15 K) / 15.4 L
Using the correct units and performing the calculation will give you the pressure in the flask at 13°C when the reaction is complete.