3 mol of solute is dissolved to make 4 L of solution. Enter molarity.
Correct Answer: 0.75
Explanation:
M=n/V=3/4=0.750 mol/L.
MCQ Collection
china-gaokao-chemistry MCQs
Practice china-gaokao-chemistry questions with answers and explanations.
Acid calculation item 2: A strong monoprotic acid has [H⁺]=1e-03 mol/L. Enter the pH.
Correct Answer: 3
Explanation:
pH=−log₁₀[H⁺]=−log₁₀(1e-03)=3.0.
Practice context 2: Which statement is consistent with Le Châtelier’s principle?
Choose an option to check your answer.
Correct Answer: D. Increasing pressure shifts a gaseous equilibrium toward the side with fewer gas moles
Explanation:
A pressure increase favours the side occupying less gaseous volume; a catalyst changes rate, not equilibrium position.
Practice context 2: Which periodic-trend statement is most accurate?
Choose an option to check your answer.
Correct Answer: C. Across a period, effective nuclear charge generally increases and atomic radius tends to decrease
Explanation:
Across a period, increasing nuclear charge with similar shielding pulls valence electrons closer.
A substance has molar mass 20 g/mol. Enter the mass of 2 mol in grams.
Correct Answer: 40
Explanation:
Use mass = amount × molar mass. Therefore mass = 2 × 20 = 40 g.
2 mol of solute is dissolved to make 3 L of solution. Enter molarity.
Correct Answer: 0.667
Explanation:
M=n/V=2/3=0.667 mol/L.
Acid calculation item 1: A strong monoprotic acid has [H⁺]=1e-02 mol/L. Enter the pH.
Correct Answer: 2
Explanation:
pH=−log₁₀[H⁺]=−log₁₀(1e-02)=2.0.
Practice context 1: Which statement is consistent with Le Châtelier’s principle?
Choose an option to check your answer.
Correct Answer: D. Increasing pressure shifts a gaseous equilibrium toward the side with fewer gas moles
Explanation:
A pressure increase favours the side occupying less gaseous volume; a catalyst changes rate, not equilibrium position.
Practice context 1: Which periodic-trend statement is most accurate?
Choose an option to check your answer.
Correct Answer: A. Across a period, effective nuclear charge generally increases and atomic radius tends to decrease
Explanation:
Across a period, increasing nuclear charge with similar shielding pulls valence electrons closer.
Practice context 1: Which statement best describes a covalent bond?
Choose an option to check your answer.
Correct Answer: B. A covalent bond forms through sharing electron density between atoms
Explanation:
Covalent bonding arises from shared electron density, commonly between nonmetal atoms.
Practice context 1: Which redox statement is correct?
Choose an option to check your answer.
Correct Answer: C. Oxidation is an increase in oxidation number and reduction is a decrease
Explanation:
Oxidation corresponds to electron loss/increased oxidation number; reduction is the opposite.
Practice context 1: How does a catalyst affect a reversible reaction?
Choose an option to check your answer.
Correct Answer: B. A catalyst lowers activation energy for both forward and reverse reactions
Explanation:
It provides a lower-energy pathway in both directions, speeding equilibrium without changing K.