Grade 12 Chemistry: Molecular Structures

• Grade 12 Chemistry practice test focuses on structures and properties of molecules.
• The test includes multiple-choice, short-answer, and diagram-based questions.
• The duration of the test is 1 hour.

Multiple Choice Questions

• Question 1 asks to identify the molecule with a tetrahedral shape, with the correct answer being methane (CH₄).
• Question 2 asks to identify the strongest intermolecular force in liquid HF, with the correct answer being hydrogen bonding.
• Question 3 asks to identify the hybridization state corresponding to a molecule with a trigonal planar shape, with the correct answer being sp².
• Question 4 asks to identify the correct molecular geometry of SF₆, with the correct answer being octahedral.
• Question 5 asks to identify the molecule containing a coordinate covalent bond, with the correct answer being NH₄⁺ (ammonium ion).

Short Answer Questions

• Question 6 requires explaining why water (H₂O) has a bent shape rather than a linear shape.
• Question 7 requires drawing the Lewis structure for CO₃²⁻ (carbonate ion) and describing its molecular geometry.
• Question 8 involves comparing and contrasting the bond polarity and molecular polarity of CH₄ and NH₃.
• Question 9 requires describing the concept of hybridization and determining the hybridization of the central atom in NH₃.
• Question 10 asks to explain why graphite conducts electricity while diamond does not, even though both are forms of carbon.

Diagrams & 3D Structures

• Question 11 requires drawing the 3D structures of methane (CH₄), ammonia (NH₃), and water (H₂O), and identifying their bond angles.
• Question 12 requires drawing a diagram that shows the coordinate covalent bond formation in NH₄⁺ (ammonium ion).

3D Molecular Structures

• Methane (CH₄) has a tetrahedral shape with a bond angle of 109.5°.
• Ammonia (NH₃) has a trigonal pyramidal shape with a bond angle of 107°.
• Water (H₂O) has a bent shape with a bond angle of 104.5°.

Bonus Question

• Question 13 focuses on the molecule XeF₄; it requires drawing its Lewis structure, identifying its molecular shape, determining the hybridization of Xe, and explaining whether the molecule is polar or nonpolar.

This practice test for Grade 12 Chemistry focuses on the structures and properties of molecules. It features multiple-choice and short-answer questions. Topics include molecular shapes, intermolecular forces, and hybridization.