Q1. What is the change in internal energy of a system that absorbs 198 kJ of heat and has 110 kJ of work done on it by the surroundings?

Background

Topic: Thermochemistry – First Law of Thermodynamics

This question tests your understanding of how heat and work contribute to the change in internal energy () of a system.

Key formula:

• = heat absorbed by the system (positive if absorbed)

• = work done on the system (positive if done on the system)

Step-by-Step Guidance

1. Identify the values: kJ (heat absorbed), kJ (work done on the system).

2. Recall that both values are positive because the system gains energy from both heat and work.

3. Set up the equation: .

4. Plug in the values for and to prepare for the calculation.

Try solving on your own before revealing the answer!

Q22. Which orbital shape does not match the description?

Background

Topic: Quantum Mechanics – Atomic Orbitals

This question tests your ability to recognize and match the visual shapes of atomic orbitals (s, p, d, f) to their correct labels.

Key Terms:

• s orbital: spherical shape

• p orbital: two lobes (balloon-like) tied at the center

• d orbital: four lobes or a donut with lobes

Step-by-Step Guidance

1. Review the visual descriptions of each orbital shape provided in the question.

2. Recall the typical shapes: s (sphere), p (two lobes), d (four lobes or donut with lobes).

3. Compare each image and description to the standard orbital shapes.

4. Identify which option does not match the expected orbital shape for its label.

Try solving on your own before revealing the answer!