2020-2029 Governor's Cup - SC - Topic 11

Buffers are solutions that resist changing pH. Which of the following can react to form a buffer?

• HCl and NaOH

• H₂CO₃ and NaHCO₃

• KCl and NaOH

• HBr and KOH

Not all salts taste salty. Some salts are insoluble, and thus cannot be tasted. Others, may taste bitter or even sweet. Which of the following salts is used as a salt substitute on foods and does taste salty?

• potassium sodium tartrate

• lead (II) acetate

• potassium chloride

• monosodium glutamate

This value is used to measure acidity of a solution and it can be visually estimated at the half-equivalence point on a titration curve. What is the negative log of the dissociation constant?

• pI

• van’t Hoff factor

• pKa

• Ka

Bronsted-Lowry acids are defined by their ability to donate a proton to another substance in solution. What is the conjugate base of the hydronium ion?

• OH⁻

• H₂O

• H₃O⁺

• H⁺

Normality refers to the number of gram equivalent weights of a solute in one liter of solution and is a measure of the solution’s concentration. What is the normality of 1 M sulfuric acid?

• 1 N

• 1.5 N

• 2 N

• 0.5 N

Match the salt with its classification:

• x – 3, y – 2, z – 1

• x – 2, y – 1, z – 3

• x – 1, y – 2, z – 3

• x – 2, y – 3, z – 1

Tags

NGSS.HS-PS1-3

In acid-base reactions, an acid plus a base reacts to form a conjugate pair. What is the conjugate acid of ammonia?

• H⁺

• NH²⁻

• NH⁴⁺

• N³⁺

According to general solubility rules, which of the following compounds is readily soluble in water?

• CaCO₃

• BaSO₄

• PbBr₂

• CH₃COONa

This entity can be used to determine colligative properties of solutions. What entity is equal to the number of particles produced by each dissolved particle within a solution?

• van’t Hoff factor

• equilibrium constant

• dissociation constant

• enthalpy of vaporization

Some salts will form an acidic solution when dissolved into a solvent. Which of the following can be considered an acidic salt when dissolved into a solvent?

• lithium fluoride

• ammonium chloride

• sodium chloride

• potassium chloride