Stoichiometry

Name the given compound - Fe₂(CO₃)₃

• iron (II) carbonate
• Iron (III) carbonate
• Iron carbonate
• Iron carbonate (II)

Determine the oxidation number of each green coloured element in the following ion : S₂O₈^2-

• +7
• -2
• -1
• +6

All alkali metal react with water to produce hydrogen gas and the corresponding alkaline metal hydroxide. A typical reaction is that between lithium and water :  2Li(s) + 2H₂O(l) →2LiOH(aq) + H₂(g) Calculate the mass of H₂ gas formed when 40.0 g of Li react with water [Ar H =1.0, Li = 6.9, O =16.0]

• 4.21 g
• 7.31 g
• 5.80 g
• 4.42 g

Urea (NH₂)₂CO is prepared by reacting ammonia with carbon dioxide :
2NH₃(g) + CO₂(g)  → (NH₂)CO(aq) + H₂O(l)
If 600.0 g of NH₃ area allowed to react with 1142 g of CO₂, determine mass of excess reactant left at the end of the reaction.

• 456.01 g
• 65.09 g
• 403.21 g
• 363.88 g

An aqueous solution of MgSO₄ is added to an aqueous solution of BaCl₂ to form BaSO₄ and MgCl₂. If 1.75 g of MgSO₄ and 2.75 g of BaCl₂ are used, calculate the mass of BaSO₄ produced after the reactant has completed. [Mr MgSO₄ = 120.4; BaCl₂ = 208.3; BaSO₄ = 233.4; MgCl₂ = 95.3]

• 2.03 g
• 1.96 g
• 3.08 g
• 1.50 g

Balance the following equation in acidic medium
aMnO₄^-(aq) + bC₂O₄^2-(aq) →cMn²⁺(aq) + dCO₂(g) + eH₂O(l)
The sum of the coefficient a+b+c+d+d

• 43
• 27
• 29
• 25

0.157 g of C₆H₇NO was used to react with 0.486 g of C₄H₆O₃ to produce C₈H₉NO₂ and CH₃COOH. After purification, 0.198 g of C₈H₉NO₂ was extracted. Determine the percentage yield of C₈H₉NO₂. [Ar C : 12.O; H=1.0; N=18; O=16.0]

• 70.09%
• 85.62%
• 91.24%
• 90.90%

Calculate the mass (in kg) of water produced from the combustion of 1.0 gallon (3.8 L) of gasoline (C₈H₁₈). The  density of gasoline is 0.79 g/mL [Mr C : 12.0; H : 1.0]

• 3.33 kg
• 7.12 kg
• 4.27 kg
• 6.57 kg

If 4.50 g of HCl is reacted with 15.0 g of CaCO₃ according to the following chemical equation,
2HCl + CaCO₃ → CaCl₂ + H2O + CO_{2
Calculate the theoretical yield (in gram) of}
CO₂

• 2.05 g
• 4.12 g
• 3.02 g
• 2.71 g

290.23 mg of ethanol (C₂H₅OH) is reacted with excess oxygen (O₂) to provide 481.11 mg of CO₂. What is the percentage yield of CO₂ in this reaction?

• 90.0 %
• 86.7 %
• 67.8 %
• 77.8 %