Taking into account the definition of avogadro's number, 0.21 moles of sulfur dioxide contain 1.26482×10²³ molecules.
Avogadro's Number or Avogadro's Constant is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023×10²³ particles per mole. Avogadro's number applies to any substance.
First you must determine the number of moles that 13.5 g of sulfur dioxide contains. For that, I use the molar mass of the compound, which is defined as the amount of mass that a substance contains in one mole.
In this case, the molar mass of sulfur dioxide is 64 g/mole. So the number of moles that 13.5 grams of the compound contain can be calculated as:
0.21 moles
Then you can apply the following rule of three: if 1 mole of sulfur dioxide contains 6.023×10²³ molecules, then 0.21 moles contain how many molecules of sulfur dioxide?
amount of molecules of sulfur dioxide= (6.023×10²³ molecules× 0.21 mole)÷ 1 mole
amount of molecules of sulfur dioxide=1.26482×10²³ molecules
Finally, 0.21 moles of sulfur dioxide contain 1.26482×10²³ molecules.
Learn more about Avogadro's Number:
T = 15°C = 288.15 K; temperature.
R = 0.08206 L·atm/mol·K, universal gas constant.
Ideal gas law: p·V = n·R·T.
p = n·R·T / V.
p = 0.00825 mol · 0.08206 L·atm/mol·K · 288.15 K / 0.174 L.
p = 1.12 atm.
The percentage yield of Hydrogen is 51.1%
We'll begin by calculating the mass of Mg that reacted and the mass of H₂ produced from the balanced equation.
Mg + 2HNO₃ → Mg(NO₃)₂ + H₂
Molar mass of Mg = 24 g/mol
Mass of Mg from the balanced equation = 1 × 24 = 24 g
Molar mass of H₂ = 2 × 1 = 2 g/mol
Mass of H₂ from the balanced equation = 1 × 2 = 2 g
From the balanced equation above,
24 g of Mg reacted to produce 2 g of H₂.
Next, we shall determine the theoretical yield of H₂.
From the balanced equation above,
24 g of Mg reacted to produce 2 g of H₂.
Therefore,
40 g of Mg will react to produce = (40 × 2) / 24 = 3.33 g of H₂.
Thus the theoretical yield of H₂ is 3.33 g
Finally, we shall determine the percentage yield of H₂.
Percentage yield = (Actual / Theoretical) × 100
Percentage yield = (1.70 / 3.33) × 100
Percentage yield of H₂ = 51.1%
Learn more about percentage yield: