Chapter 10 Homework - CHEM 60

What is the relationship between the hydroxide ion and a water molecule?

A hydroxide ion is a water molecule minus a hydrogen nucleus.

F- (aq) + H2O (l) -> HF (aq) + OH- (aq)

Acid (proton donor) H2O, proton acceptor (base) F-

H2SO4 (aq) + H2O (l) -> H3O+ (aq) + HSO4- (aq)

Acid (proton donor) H2SO4, proton acceptor (base) H2O

Sulfuric acid reacts with water to yield hydrogen sulfate ions and hydronium ions: H2SO4 + H2O -> HSO4- + H3O+ Identify the conjugate acid-base pairs

Acid: H2SO4 Conjugate base: HSO4- Base: H2O Conjugate acid: H3O+

Hydrogen sulfate reacts with water to produce sulfate ions and hydronium ions: HSO4- + H2O -> SO4^2- + H3O+ Identify the conjugate acid-base pairs

Acid: HSO4- Conjugate base: SO4^2- Base: H2O Conjugate acid: H3O+

Rain, pH 5.8

Acidic

Shampoo, pH 5.7

Acidic

Soda, pH 3.2

Acidic

For the following reaction, identify whether the compound in bold is behaving as an acid or a base. H3PO4 + H2O ⇌ H2PO4- + H3O+

Base

H2PO4- is the conjugate (blank) of H3PO4 and the conjugate (blank) of HPO4^2-

Base / acid

Laundry detergent, pH 9.4

Basic

Sometimes an individual going through a traumatic experience cannot stop hyperventilating. In such a circumstance, it is recommended that the individual breathe into a paper bag or cupped hands as a useful way to avoid an increase in blood pH, which can cause the person to pass out. Explain how this works.

CO2 initially exhaled is reinhaled to help maintain adequate levels of carbonic acid in the blood.

Hydrogen chloride is added to a buffer solution of ammonia, NH3, and ammonium chloride, NH4Cl What is the effect on the concentration of ammonia? On the concentration of ammonium chloride?

Concentration of ammonia decreases Concentration of ammonium chloride increases

According to the following reaction, which molecule is acting as an acid? H2O + NH3 -> OH- + NH4+

H2O

For the following acid-base reaction, identify what compound is formed in the space marked H2SO4 + KOH -> KHSO4 + ????

H2O

According to the following reaction, which molecule is acting as an acid? H2O + H2SO4 -> H3O+ + HSO4-

H2SO4

According to the following reaction, which molecule is acting as an acid? H3O+ + HSO4- -> H2O + H2SO4

H3O+

According to the following reaction, which molecule is acting as an base? H3O+ + HSO4- -> H2O + H2SO4

HSO4-

Why do we use the pH scale to indicate the acidity of a solution rather than simply stating the concentration of hydronium ions?

It is more convenient, since the concentration of hydronium ions is usually so small.

For the following acid-base reaction, identify what compound is formed in the space marked HNO3 + KOH -> ???? + H2O

KNO3

A weak acid is added to a concentrated solution of hydrochloric acid. Does the solution become more or less acidic?

Less acidic, since the solution becomes more dilute with a less concentrated solution of hydronium ions being added to the solution.

According to the following reaction, which molecule is acting as an base? H2O + NH3 -> OH- + NH4+

NH3

According to the following reaction, which molecule is acting as an acid? OH- + NH4+ -> H2O + NH3

NH4+

The hydronium ion, H3O+, is a

Polyatomic ion Proton donor

Which of the following compounds could never act as an acid?

SO4 2- PO4 3- CO3 2-

What best describes what happens when an acid such as HCl is mixed with water?

The proton chemically bonded to the chlorine is transferred to a water molecule and forms a chloride ion and a hydronium ion.

For the following reaction, identify whether the compound in bold is behaving as an acid or a base. H3PO4 + H2O ⇌ H2PO4- + H3O+

acid

What is a base?

anything that accepts a hydrogen ion

When the hydronium ion concentration equals 1 mole per liter, what is the pH of the solution? Is the solution acidic or basic?

pH = 0, this is an acidic solution.

When the hydronium-ion concentration of a solution is 0.1 M, what is the pH of the solution?

pH = 1 Acidic

When the hydronium-ion concentration of a solution is 1x10^-6 M, what is the pH of the solution?

pH = 6 Acidic

What is pH an aqueous solution, which has a hydroxide-ion concentration of 1x10^-6 M?

pH = 8