Answer:
Mass = 357.7 g
Explanation:
Given data:
Mass of Fe = 250 g
Mass of oxygen = 120 g
Mass of iron(III) oxide produced = ?
Solution:
Chemical equation:
4Fe + 3O₂ → 2Fe₂O₃
Number of moles of Fe:
Number of moles = mass/molar mass
Number of moles = 250 g/ 55.8 g/mol
Number of moles = 4.48 mol
Number of moles of O₂ :
Number of moles = mass/molar mass
Number of moles = 120 g/ 32 g/mol
Number of moles = 3.75 mol
Now we will compare the moles of reactants with product.
Fe : Fe₂O₃
4 : 2
4.48 : 2/4×4.48 = 2.24
O₂ : Fe₂O₃
3 : 2
3.75 : 2/3×3.75= 2.5
Less number of moles of Fe₂O₃ are produced by Fe thus it will act as limiting reactant.
Mass of Fe₂O₃:
Mass = number of moles × molar mass
Mass = 2.24 mol × 159.69 g/mol
Mass = 357.7 g
Answer:
a. HCl + NH₃ ⇄ NH₄Cl
b. KOH + NH₄⁺ ⇄ K⁺ + NH₃ + H₂O
Explanation:
A buffer system is made by a weak base (ammonia, NH₃) and its conjugate acid (ammonium ion NH₄⁺ coming from ammonium chloride NH₄Cl). Its function is to resist abrupt changes in the pH when acids or bases are added.
a. When aqueous hydrochloric acid is added, it reacts with the base of the buffer. The corresponding equation is:
HCl + NH₃ ⇄ NH₄Cl
b. When aqueous potassium hydroxide is added, it reacts with the acid of the buffer. The corresponding equation is:
KOH + NH₄⁺ ⇄ K⁺ + NH₃ + H₂O