Biology Chapter: Equilibrium and Water Properties

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Questions and Answers

What happens to the rate of the forward reaction when the concentration of the reactants decreases at equilibrium?

It becomes the same as the reverse reaction.

It remains the same.

It decreases. (correct)

It increases immediately.

Which principle explains the shift in equilibrium when a concentration change occurs?

The Ideal Gas Law

Raoult's Law

The Law of Conservation of Mass

Le Châtelier’s Principle (correct)

What occurs to oxygen transport in hyposia conditions?

Oxygen levels remain unchanged.

Oxygen is released from hemoglobin. (correct)

Oxygen levels double in the tissues.

Oxygen is entirely retained by hemoglobin.

What can occur to the body after adapting to high altitude for about 10 days?

Increased red blood cell production Signup and view all the answers

What characterizes hypoxia?

Cyanosis in the skin Signup and view all the answers

At high altitudes, how much less oxygen does a person obtain compared to sea level?

29% less Signup and view all the answers

According to the oxygen-hemoglobin equilibrium, what happens when oxygen levels are high?

Oxygen binds to hemoglobin, forming oxyhemoglobin. Signup and view all the answers

What immediate treatments are recommended for altitude sickness?

Hydration, rest, and descending to a lower altitude Signup and view all the answers

What unique feature does water have regarding its density at different states?

Water is less dense in its solid state than in its liquid state. Signup and view all the answers

What role do hydrogen ions and hydroxide ions play in biological systems?

They are critical determinants of the structure and function of biomolecules. Signup and view all the answers

What property of water causes it to have a high boiling point and heat of vaporization?

Its high intermolecular forces due to hydrogen bonding. Signup and view all the answers

How does the polarity of water affect its behavior as a solvent?

Water can dissolve ionic and polar substances effectively. Signup and view all the answers

What is a key reason for water's high surface tension?

The strong intermolecular forces between water molecules. Signup and view all the answers

What is the term for the phenomenon where a difference in hydrogen ion concentration across a membrane creates energy?

Membrane potential. Signup and view all the answers

What is the significance of water's heat of vaporization in biological systems?

It contributes to cooling mechanisms in organisms. Signup and view all the answers

What characteristic does water exhibit due to permanent dipoles in its molecules?

It exhibits strong cohesive properties. Signup and view all the answers

Which statement accurately describes the effect of solutes on the structure of liquid water?

Solutes fix nearby water molecules in a more ordered array. Signup and view all the answers

What is the primary characteristic of colligative properties?

They are determined only by the concentration of solute. Signup and view all the answers

Which of the following is an example of a colligative property?

Freezing point depression. Signup and view all the answers

How does osmotic pressure relate to the contents of a cell's cytosol?

Osmotic pressure increases with the number of free glucose molecules. Signup and view all the answers

What effect does boiling point elevation have on a solution with dissolved substances?

It increases the temperature at which the solution boils. Signup and view all the answers

What is the primary reason for freezing point depression when using rock salt?

Rock salt causes solutes to disrupt the liquid water structure. Signup and view all the answers

How does vapor pressure relate to the transition of water from liquid to gas?

Vapor pressure is the pressure exerted when water is in equilibrium. Signup and view all the answers

The process of creating micelles involves interaction with which type of molecules?

Amphiphilic molecules containing both polar and nonpolar groups. Signup and view all the answers

What characterizes Brønsted-Lowry acids and bases?

They always exist as conjugate acid-base pairs. Signup and view all the answers

Which type of arrow is used to represent the ionization of strong acids?

Single arrow Signup and view all the answers

What is the pH of a 0.15 M solution of hydrochloric acid?

0.85 Signup and view all the answers

Which statement is true regarding strong acids and bases?

Strong acids completely dissociate in water. Signup and view all the answers

If a solution has a pH of 8.5, what is the molarity of hydrogen ions in the solution?

3.16 x 10^-8 M Signup and view all the answers

What is the relationship between pH and pOH in aqueous solutions?

pH + pOH = 14 Signup and view all the answers

What is the pH of a solution if the hydronium ion concentration is $1.7 x 10^{-3} M$?

2.77 Signup and view all the answers

Which hydroxides are typically considered strong bases?

Hydroxides of Group I and Group II metals Signup and view all the answers

What is the primary function of bicarbonate in the body's buffering system?

To maintain a stable pH by neutralizing excess acids. Signup and view all the answers

What condition is characterized by a decrease in carbon dioxide levels leading to a higher blood pH?

Alkalosis Signup and view all the answers

What substance is produced from the dissociation of carbonic acid in the bicarbonate buffer system?

H3O+ and HCO3- Signup and view all the answers

What do the kidneys primarily regulate in the bicarbonate buffer system?

HCO3- and H+ ions Signup and view all the answers

What is a limitation of the carbonic acid buffer system?

Its buffering ability is limited by the availability of bicarbonate ions. Signup and view all the answers

Which enzyme is involved in the bicarbonate buffer reactions within the body?

Carbonic anhydrase Signup and view all the answers

Which process helps lower blood pH in response to an increase in H3O+ concentration?

Kidneys excrete bicarbonate. Signup and view all the answers

What happens to the equilibrium of the bicarbonate buffer system when CO2 levels rise?

It shifts to produce more H3O+, lowering pH. Signup and view all the answers

Where is the phosphate buffer primarily found in high concentrations?

Intracellular fluid Signup and view all the answers

What is the optimum pH for the phosphate buffer to function effectively?

6.8 Signup and view all the answers

Which group of molecules can respond to pH changes by accepting or releasing H+?

Amino acids Signup and view all the answers

What does hemoglobin help to transport in addition to CO2?

Hydrogen and oxygen Signup and view all the answers

What effect does hyperventilation have on blood pH?

Raises pH due to removal of H+ Signup and view all the answers

Which systems are responsible for renal regulation?

Kidneys and lungs Signup and view all the answers

What happens during hypoventilation in relation to pH balance?

Increased H+ causes pH to decrease Signup and view all the answers

What is a crucial role of the kidneys in maintaining pH balance?

Conserving and producing bicarbonate ions Signup and view all the answers

Study Notes

Chapter 2: Water: The Medium of Life

Life originated, evolved, and thrives in the seas. The timeline of evolution showcases initial aquatic environments, transitioning periods, and the eventual development of terrestrial environments. Key periods such as 395 million years ago (mya) and 340 mya are illustrative of these evolutionary stages.
Water and its ionization products (hydrogen ions and hydroxide ions) are crucial for the structure and function of biological molecules (amino acids, proteins, nucleotides, nucleic acids, phospholipids, and membranes).
A difference in hydrogen ion concentration on opposite sides of a membrane creates an energized state essential for energy transformation processes in biological systems. This difference is frequently discussed in the context of cellular energy production.
Water has unusually high boiling, melting points, heat of vaporization, and surface tension due to strong intermolecular forces of attraction between water molecules. This is anomalously high for substances of similar molecular weight that aren't metallic or ionic.
Water's maximum density is found in the liquid state, not the solid state (ice). This means ice occupies more space than liquid water.
Permanent dipoles in water molecules occur because of differing electronegativities between oxygen and hydrogen atoms, creating partial charges (δ- and δ+).
Hydrogen bonds in water are crucial for its properties. These bonds allow water to participate in a variety of chemical and physical interactions, affecting its behavior and properties.

2.1 What Are the Properties of Water?

Water's high boiling, melting points, heat of vaporization, and surface tension are attributed to the strong intermolecular forces between water molecules. These forces create a significantly ordered structure within liquid water compared to other substances of similar molecular weights which are not metallic nor ionic.
Water's unique properties are linked to its polar nature; the uneven distribution of electrons within a water molecule leads to partial charges, forming polar bonds.
The solvent properties of water stem from its polar nature. Water readily dissolves many polar and ionic compounds (and some nonpolar) as opposed to other solvents. This is due to its ability to form hydration shells around ions and polar substances.
The high dielectric constant of water allows it to weaken the attractive forces between oppositely charged ions, and hydrate them.
Water's ability to form hydrogen bonds with polar molecules is crucial for its solvent properties and it is a key driving force in these interactions.
Hydrophobic interactions result as nonpolar solutes disrupt the ordered structure of water, and water molecules cluster around them, creating a cage-like structure.
Interacting with amphiphilic compounds (having both polar and nonpolar regions) in water results in the formation of micelles; these structures sequester the nonpolar parts from water to maximize entropy.

2.1 Colligative Properties

The presence of dissolved substances affects the properties of water (e.g., freezing point depression, boiling point elevation, vapor pressure lowering, osmotic pressure effects). These effects are the same regardless of the identity of the solute, instead dependent on the concentration of solute in the solution.
Solutes increase the order of water molecules surrounding them, making it harder for water to freeze or boil. Solutes also affect osmosis, the movement of water across a selectively permeable membrane.

2.2 What is pH?

pH is a measure of the concentration of hydrogen ions in an aqueous solution. A low pH indicates a high concentration of hydrogen ions, while a high pH indicates a low concentration.
pH is described as the power of hydrogen. The pH scale is logarithmic which means that each whole number change in pH represents a tenfold change in H+ concentration.
Neutral solutions have an equal concentration of hydrogen and hydroxide ions ([H+]=[OH-]).
Acidic solutions have a greater concentration of hydrogen ions than hydroxide ions ([H+] > [OH-]).
Basic (or alkaline) solutions have a lower concentration of hydrogen ions than hydroxide ions ([H+] < [OH-]).

2.3 What are buffers and what do they do?

The lungs and kidneys are the main organs regulating pH in body fluids.
A buffer helps resist large pH changes. Buffer systems use a conjugate acid-base pair to resist drastic pH changes when hydrogen ions are added or lost to the solution.

Other Information

The ionization constant of water (Kw) relates the concentrations of hydrogen and hydroxide ions to the specific temperature at which it is measured. The value of Kw changes depending on temperature.
Strong acids completely dissociate in water, whereas weak acids only partially dissociate. This dissociation leads to different behaviors in solutions of these two different categories of acids.
The important buffer systems in the body are the bicarbonate buffer and the phosphate buffer. These act in conjunction with the physiological buffers, the lungs and the kidneys, to maintain the blood pH within a stable range.
The respiratory system, by controlling carbon dioxide levels, adjusts the carbonic acid-bicarbonate buffer system. Specifically by altering the rate and depth of breathing.
The renal system, through complex processes, regulates and controls the bicarbonate concentration, reabsorption and excretion mechanisms. This is a slow process than lung pH adjustment.
The combined action of the lungs and kidneys, along with chemical buffers, work together to help keep pH within a normal range.

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Description

This quiz explores key concepts in biology related to equilibrium, oxygen transport under hypoxia, and the unique properties of water. Dive into questions about reaction rates, altitude adaptation, and the significance of hydrogen and hydroxide ions in biological systems. It's designed for students looking to understand these fundamental scientific principles.