1. To determine the theoretical yield of PCl5 (s), you need to use stoichiometry and the given amounts of reactants.
First, convert the mass of phosphorus (P4) to moles by using the molar mass of phosphorus. Since the molar mass of P4 is 123.895 g/mol, divide the given mass (10.00 g) by the molar mass:
10.00 g P4 / 123.895 g/mol = 0.0807 mol P4
Next, convert the mass of chlorine gas (Cl2) to moles using the molar mass of chlorine. The molar mass of Cl2 is 70.906 g/mol, so divide the given mass (220 g) by the molar mass:
220 g Cl2 / 70.906 g/mol = 3.10 mol Cl2
Next, determine the limiting reactant by comparing the mole ratios between phosphorus and chlorine. From the balanced equation, the mole ratio of P4 to Cl2 is 1:5.
Since there are fewer moles of phosphorus (0.0807 mol) compared to chlorine (3.10 mol), phosphorus is the limiting reactant.
The theoretical yield is determined by the stoichiometry of the balanced equation. From the balanced equation: P4 (s) + Cl2 (g) → PCl5 (s), the mole ratio of P4 to PCl5 is 1:1.
Therefore, 0.0807 mol of P4 will produce 0.0807 mol of PCl5.
Finally, calculate the mass of PCl5 using the molar mass of PCl5 (208.225 g/mol):
0.0807 mol PCl5 x 208.225 g/mol = 16.85 g PCl5 (rounded to two decimal places)
So, the theoretical yield of PCl5 (s) is 16.85 grams.
2. The condensation of the beaker of cold water when a blue flame is passed underneath is due to the product of water vapor (H2O) from combustion. When the blue flame is passed over or near a cold surface, it cools down the surrounding air, causing the water vapor present in the air to condense back into liquid water, resulting in the formation of condensation. Therefore, the correct answer is (A) the product of water (H2O) from combustion.
3. The reaction of hydrogen peroxide (H2O2) in the presence of manganese dioxide (MnO2) produces oxygen gas (O2). The balanced chemical equation for this reaction is:
2 H2O2 (aq) → 2 H2O (l) + O2 (g)
Therefore, the correct answer is (B) oxygen gas.
4. To determine the concentration of Ca(OH)2, you need to use the concept of stoichiometry and the data from the titration.
First, write the balanced equation for the reaction between NaOH and H2SO4:
H2SO4 (aq) + 2 NaOH (aq) → Na2SO4 (aq) + 2 H2O (l)
From the balanced equation, you can see that the stoichiometric ratio between H2SO4 and NaOH is 1:2. So, 1 mole of H2SO4 reacts with 2 moles of NaOH.
Use the given data from the titration:
Initial volume of H2SO4 = 13.28 mL
Final volume of H2SO4 = 28.29 mL
Calculate the volume of H2SO4 used in the titration:
Volume of H2SO4 used = Final volume - Initial volume
= 28.29 mL - 13.28 mL
= 15.01 mL
Now, use the molarity and volume data to calculate the number of moles of H2SO4 used:
Moles of H2SO4 = Molarity × Volume (in liters)
= 0.250 M × (15.01 mL / 1000 mL/liter)
= 0.0037525 mol H2SO4
Since the stoichiometric ratio between H2SO4 and NaOH is 1:2, the number of moles of NaOH used in the titration is twice that of H2SO4:
Moles of NaOH = 2 × Moles of H2SO4
= 2 × 0.0037525 mol NaOH
= 0.007505 mol NaOH
Now, calculate the concentration of NaOH by dividing the moles of NaOH by the volume in liters:
Concentration of NaOH = Moles of NaOH / Volume (in liters)
= 0.007505 mol NaOH / (21.18 mL / 1000 mL/liter)
= 0.3538 M NaOH
Therefore, the concentration of Ca(OH)2 is 0.3538 M.
5. Precipitation occurs when two solutions are mixed and a solid substance is formed and separates from the solution. This can be observed by a change in appearance such as cloudiness or the formation of visible solid particles suspended in the solution. Therefore, the correct answer is (B) when you can't see through it, indicating the formation of a precipitate.