Hello, please can some one help me in chemistry (gaseous section) exercises?

2.
4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(g)
Mole ratio NH₃ : NO = 4 : 4 = 1 : 1

No. of moles of NH₃ reacted (given) = 10⁶ mol
No. of moles of NO obtained = 10⁶ mol

Molar volume of a gas at S.T.P. = 22.4 L mol⁻¹
Volume of NO obtained at S.T.P. = (10⁶ mol) × (22.4 L mol⁻¹) = 22.4 × 10⁶ L

At S.T.P. : P₁ = 1.01 bars, V₁ = 22.4 × 10⁶ L, T₁ = 273 K
At given conditions : P₂ = 5 bars, V₂ = ? L, T₂ = (273 + 850) K = 1123 K

P₁V₁/T₁ = P₂V₂/T₂
Then, V₂ = V₁ × (P₁/P₂) × (T₂/T₁)

Volume of NO obtained at the given conditions = (22.4 × 10⁶ L) × (1.01/5) × (1123/273) = 1.86 × 10⁷ L


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3.
a)
Molar mass of H₂ = 1.0 × 2 g/mol = 2.0 g/mol
Molar mass of N₂ = 14.0 × 2 g/mol = 28.0 g/mol

No. of moles of H₂ = (6.00 g) / (2.0 g/mol) = 3.00 mol
No. of moles of N₂ = (7.00 g) / (28.0 g/mol) = 0.25 mol
Total no. of moles of gases = (3.00 + 0.25) mol = 3.25 mol

Molar fraction of H₂ = 3.00/3.25 = 12/13
Molar fraction of N₂ = 0.25/3.25 = 1/13

b)
Total pressure, P = ? atm
Volume, V = 15 L
Absolute temperature, T = 273 K
R = 8.314 J mol⁻¹ K⁻¹

For a fixed amount of gas : PV = nRT
Then, P = nRT/V

Total pressure, P = 3.25 × 8.314 × 273 / 15 kPa = 492 kPa

c)
Partial pressure of H₂ = (492 kPa) × (12/13) = 454 kPa
Partial pressure of N₂ = (492 kPa) × (1/13) = 38 kPa