Tahsili Chemistry 2

Question 1

What is Le Chatelier's Principle?

Accepted Answer

If a system at equilibrium is disturbed, it shifts to counteract the change and restore equilibrium

Answer

Le Chatelier's Principle states that when a system at equilibrium is subjected to a change (concentration, temperature, pressure), the system adjusts to partially counteract the change. For example, adding reactant shifts equilibrium toward products.

Question 2

What is the difference between an exothermic and endothermic reaction?

Accepted Answer

Exothermic releases heat to surroundings (ΔH < 0); endothermic absorbs heat from surroundings (ΔH > 0)

Answer

Exothermic reactions release energy as heat (products have lower energy, ΔH negative): e.g., combustion. Endothermic reactions absorb energy (products have higher energy, ΔH positive): e.g., photosynthesis, dissolving ammonium nitrate.

Question 3

In a galvanic cell, what happens at the anode?

Accepted Answer

Oxidation occurs — the anode loses electrons

Answer

At the anode, oxidation occurs (loss of electrons). Remember: AN OX, RED CAT — ANode = OXidation, REDuction = CAThode. The anode is the negative electrode in a galvanic cell. Electrons flow from anode to cathode through the external circuit.

Question 4

What is the molecular geometry of methane (CH₄)?

Accepted Answer

Tetrahedral

Answer

Methane has 4 bonding pairs around the central carbon with no lone pairs (AX₄ by VSEPR theory), giving a tetrahedral geometry with 109.5° bond angles. This is the most stable arrangement for 4 electron pairs.

Question 5

What is the molarity of a solution containing 4 moles of NaCl in 2 liters of solution?

Accepted Answer

2 M

Answer

Molarity (M) = moles of solute / liters of solution = 4 mol / 2 L = 2 M. Molarity is the most commonly used concentration unit in chemistry.

Tahsili Practice Test

Tahsili Practice Test

Tahsili Chemistry 2