MCQs

The balanced equation indicates a 1 : 1 mole ratio between CaCO₃ and CO₂. Therefore, 2.5 moles of CaCO₃ yield 2.5 moles of CO₂. Concept tested: Stoichiometric mole calculations.

The balanced equation shows a 2 : 2 ratio between Na and NaCl, which simplifies to 1 : 1. Therefore, 5 moles of Na produce 5 moles of NaCl. Concept tested: Mole ratio from a balanced equation.

Stoichiometric calculations depend on the coefficients of a balanced equation because they represent mole ratios. Physical states, temperature, and reaction rate are not sufficient for quantitative calculations. Concept tested: Importance of balanced equations in stoichiometry.

At the same conditions of temperature and pressure, gas volumes follow mole ratios. One volume of O₂ produces two volumes of gaseous H₂O. Thus, 44.8 L O₂ forms 89.6 L H₂O(g). Concept tested: Gas volume ratios at STP.

Sodium is an element consisting of atoms, so one mole contains Avogadro's number of atoms, not molecules. Concept tested: Representative particles.

According to the balanced equation, 2 moles of KClO₃ produce 3 moles of O₂. Therefore, 4 moles produce 6 moles of O₂. Concept tested: Stoichiometric calculations using balanced equations.

The balanced equation shows a 1 : 1 mole ratio between CH₄ and CO₂. Thus, 3 moles of methane produce 3 moles of carbon dioxide. Concept tested: Mole ratio application.

At STP (0°C and 1 atm), one mole of any ideal gas occupies 22.4 L. Values like 24.0 L apply approximately at room temperature, not STP. Concept tested: Molar volume of gases.

The molar mass of H₂O is 18 g mol⁻¹. Therefore, 18 g represents exactly one mole. Concept tested: Mass-mole relationship.

Avogadro's number is 6.02 × 10²³ representative particles per mole. The other values are incorrect multiples or fractions. Concept tested: Avogadro's constant.

From the equation, 1 mole of N₂ reacts with 3 moles of H₂. Therefore, 2 moles of N₂ require 6 moles of H₂. Concept tested: Stoichiometric mole calculations.

The coefficients in a balanced equation represent mole ratios. Here, 2 moles of H₂ react with 1 mole of O₂. The other ratios do not match the balanced equation. Concept tested: Mole ratio from a balanced equation.

Feedback inhibition stops metabolic pathways once sufficient end product has accumulated, conserving cellular energy and raw materials. Concept tested: Biological importance of feedback inhibition.

Selective enzyme inhibitors reduce disease processes while minimizing damage to healthy tissues, making them effective therapeutic agents. Concept tested: Clinical application of enzyme inhibitors.

Non-competitive inhibitors reduce catalytic efficiency without necessarily affecting substrate binding. Concept tested: Interpretation of enzyme inhibition experiments.

Heavy metals bind strongly to functional groups of enzymes, permanently reducing their catalytic activity and disrupting metabolism. Concept tested: Toxicological effects of heavy metals.

Enzyme inhibitors are essential regulators that maintain metabolic balance and cellular homeostasis. The other options would be harmful to living organisms. Concept tested: Physiological significance of inhibition.

Non-competitive inhibitors alter the enzyme's shape, reducing catalytic efficiency without directly blocking substrate binding. Concept tested: Allosteric inhibition.

In feedback inhibition, the final product usually inhibits the first committed enzyme, preventing unnecessary synthesis of additional product. Concept tested: Mechanism of feedback inhibition.