Chemistry Flashcards

Which type of intermolecular force is responsible for the unusually high boiling point of water compared to other small molecules?

Answer: Hydrogen bonding

Water's high boiling point results from hydrogen bonding, which occurs between the partially positive hydrogen atoms and the lone pairs on oxygen atoms of neighboring molecules.

What is the hybridization of the carbon atom in CO2?

Answer: sp

Carbon in CO2 forms two double bonds with no lone pairs, resulting in sp hybridization and a linear molecular geometry.

A buffer solution is most effective when the pH of the solution is:

Answer: Equal to the pKa of the weak acid

A buffer works best when pH = pKa, because at this point the concentrations of the weak acid and its conjugate base are equal, providing maximum buffering capacity.

Which quantum number describes the orientation of an orbital in space?

Answer: Magnetic quantum number (ml)

The magnetic quantum number (ml) specifies the orientation of an orbital in three-dimensional space relative to the other orbitals in the same subshell.

In a galvanic cell, oxidation occurs at the:

Answer: Anode

Oxidation (loss of electrons) always occurs at the anode; in a galvanic cell, electrons flow from the anode through the external circuit to the cathode.

Which of the following best describes an endothermic reaction?

Answer: Products have higher energy than reactants and ΔH is positive

In an endothermic reaction, energy is absorbed from the surroundings, so products have higher energy than reactants and ΔH > 0.

What is the molarity of a solution made by dissolving 4.0 g of NaOH (molar mass = 40 g/mol) in enough water to make 500 mL of solution?

Answer: 0.2 M

Moles of NaOH = 4.0 g ÷ 40 g/mol = 0.10 mol; Molarity = 0.10 mol ÷ 0.500 L = 0.20 M.