H2 Chemistry Flashcards

What is the role of a homogeneous catalyst?

Answer: A catalyst in the same phase as the reactants

A homogeneous catalyst is in the same phase (state) as the reactants, e.g., H⁺ ions catalysing ester hydrolysis in aqueous solution.

What is the shape and bond angle of a water molecule?

Answer: Bent/V-shaped, 104.5°

Water has 2 bonding pairs and 2 lone pairs. VSEPR: the basic geometry is tetrahedral, but the shape (considering only atoms) is bent/V-shaped with a bond angle of approximately 104.5°.

What is a zwitterion?

Answer: A dipolar ion having both positive and negative charges simultaneously, as in amino acids at their isoelectric point

A zwitterion is a molecule that contains both a positive charge (–NH₃⁺) and a negative charge (–COO⁻) simultaneously, with an overall neutral charge. Amino acids exist as zwitterions at their isoelectric pH.

Calculate the cell potential (E°cell) for the following: E°(Zn²⁺/Zn) = -0.76V and E°(Cu²⁺/Cu) = +0.34V.

Answer: +1.10V

E°cell = E°cathode - E°anode = +0.34 - (-0.76) = +1.10V. Cu²⁺ is reduced at cathode; Zn is oxidised at anode.

Which type of isomerism is exhibited by cis-but-2-ene and trans-but-2-ene?

Answer: Geometric (E/Z) isomerism

Cis- and trans-but-2-ene are geometric (cis-trans or E/Z) isomers — they have the same structural formula but different spatial arrangements of groups around the C=C double bond.

What is the effect of increasing temperature on an exothermic reaction at equilibrium?

Answer: Equilibrium shifts left, more reactants

For an exothermic reaction, heat is a product. Increasing temperature applies stress that the system opposes by absorbing heat (shifting left), increasing reactants and decreasing products. Kc decreases.