Water, Acids-Bases, and Buffer Systems
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Questions and Answers

What property of water allows it to be an effective solvent?

  • Dipolar nature (correct)
  • High specific heat capacity
  • Low density in solid form
  • High boiling point

    • Oxygen is less electronegative than hydrogen in a water molecule.

    False

    What type of bond forms between the oxygen and hydrogen atoms within a water molecule?

    Covalent bond

    Water is known as the _____ solvent because it can dissolve many types of substances.

    <p>universal</p> Signup and view all the answers

    Match the following properties of water with their descriptions:

    <p>Covalent bond = Bond within a water molecule Hydrogen bond = Bond between water molecules Dipolar molecule = Molecule with partly positive and negative ends Electronegativity = Ability to attract electrons</p> Signup and view all the answers

    What role does water play in cellular compartments?

    <p>It facilitates the movement of molecules.</p> Signup and view all the answers

    Water cannot separate charged molecules.

    <p>False</p> Signup and view all the answers

    Define the role of water as a universal solvent.

    <p>Water dissolves and transports compounds essential for life.</p> Signup and view all the answers

    Water plays a role in __________ by dissipating heat.

    <p>thermoregulation</p> Signup and view all the answers

    Match the following properties of water with their functions:

    <p>Solvent = Dissolves compounds Thermal stability = Regulates temperature Chemical reactivity = Participates in reactions Polarity = Separates ions</p> Signup and view all the answers

    Which of the following is NOT a function of water?

    <p>Creating energy</p> Signup and view all the answers

    Water has no role in transporting compounds in the blood.

    <p>False</p> Signup and view all the answers

    What makes water a good solvent for many substances?

    <p>Its polar structure allows it to dissolve ionic and polar substances.</p> Signup and view all the answers

    What is the term for substances that do not interact well with water?

    <p>Hydrophobic</p> Signup and view all the answers

    The cations in ionic substances are attracted to the positive ends of water molecules.

    <p>False</p> Signup and view all the answers

    What determines the solubility of a substance in a solvent?

    <p>Type of solute and solvent, temperature, and pressure.</p> Signup and view all the answers

    A solution is a homogenous mixture of a _______ and a _______.

    <p>solute, solvent</p> Signup and view all the answers

    Match the types of solutions with their examples:

    <p>Gas-Gas = Air Gas-Liquid = CO2 in H2O Solid-Liquid = NaCl in H2O Solid-Solid = Steel (Fe + C)</p> Signup and view all the answers

    Which of the following factors affects the speed of dissolving?

    <p>Temperature</p> Signup and view all the answers

    All ionic substances dissolve equally well in water.

    <p>False</p> Signup and view all the answers

    Define amphiphilic substances.

    <p>Substances that have both polar and non-polar regions.</p> Signup and view all the answers

    How is weight percentage (w/w) calculated?

    <p>Weight of solute in 100 g of solution</p> Signup and view all the answers

    An acid can accept hydrogen ions.

    <p>False</p> Signup and view all the answers

    What does molarity (M) represent in a solution?

    <p>Moles of solute in 1L of solution</p> Signup and view all the answers

    A 5% NaCl solution contains ______ g of NaCl in 100 mL of solution.

    <p>5</p> Signup and view all the answers

    Match the following solutions with their components:

    <p>37% HCl = 37 g HCl in 100 g solution 5% EtOH = 5 mL EtOH in 100 mL solution 5% NaCl = 5 g NaCl in 100 mL solution 3M NaCH2COOH = 3 mol NaCH2COOH in 1L solution</p> Signup and view all the answers

    What is the correct formula for Weight:Volume percentage (w/v)?

    <p>Weight of solute in 100 mL solution</p> Signup and view all the answers

    An amphoteric substance can only act as an acid.

    <p>False</p> Signup and view all the answers

    Explain what happens when an acid ionizes.

    <p>It produces a proton and a base.</p> Signup and view all the answers

    What is the conjugate base of acetic acid?

    <p>Acetate</p> Signup and view all the answers

    Strong acids partially ionize in water.

    <p>False</p> Signup and view all the answers

    Define pH.

    <p>pH is the negative logarithm to the base 10 of the hydrogen ion concentration.</p> Signup and view all the answers

    Bicarbonate (HCO3-) is the conjugate base of ___________ acid.

    <p>carbonic</p> Signup and view all the answers

    Match the following acids with their conjugate bases:

    <p>Acetic acid = Acetate Citric acid = Citrate Bicarbonate = Carbonate Pyruvic acid = Pyruvate</p> Signup and view all the answers

    How does the pH in the blood generally range?

    <p>7.35 to 7.45</p> Signup and view all the answers

    Buffers are solutions that stabilize pH by combining weak acids and strong bases.

    <p>False</p> Signup and view all the answers

    What is the effect of adding an acid or base to a buffer system?

    <p>It minimizes pH changes.</p> Signup and view all the answers

    Study Notes

    Water, Acids-Bases, and Buffer Systems

    • Learning Objectives:
      • Recognize water structure
      • Relate water structure to solubility
      • Calculate solution concentrations
      • Define acids and bases
      • Describe buffers

    Water

    • Water's properties are crucial for understanding biological molecules' interactions.

    • Water structure is important.

    Water Composition

    • Total body water (about 60% of body weight in adults)

      • Intracellular fluid (ICF) ~ 40% of body weight
      • Extracellular fluid (ECF) ~ 20% of body weight
        • Plasma ~ 20% of ECF
        • Interstitial fluid ~80% of ECF

    • Composition varies by age.

    Water as a Universal Solvent

    • Water is the solvent of life.
    • Dissolves and transports compounds in blood.
    • Moves molecules within and through cell compartments.
    • Separates charged molecules.
    • Dissipates heat (regulates temperature).
    • Participates in chemical reactions.

    Solubility

    • Water's polarity is responsible for its role as a solvent.
    • Water dissolves many substances making it "the universal solvent".
    • Ionic substances dissolve in water due to the attraction of ions to water's charged ends.
      • Cations (positive ions) are attracted to the negative ends of water molecules.
      • Anions (negative ions) are attracted to the positive ends of water molecules.
    • Polar molecules can interact with water (hydrophilic).
    • Nonpolar molecules do not interact with water (hydrophobic).
    • Amphipathic molecules have both a polar and a nonpolar region, exhibiting both hydrophilic and hydrophobic behaviors.

    Solutions

    • Homogenous mixture of two or more substances.
      • Major component is the solvent
      • Minor component(s) is the solute
    • Types of solutions (gas in gas, Liquid in Liquid, solid in solid etc.)
      • Examples (Air, Saltwater)

    Factors Affecting Solubility

    • Type of solute and solvent
    • Temperature
    • Pressure
    • Common ion effect

    Factors Affecting Dissolving Speed

    • Temperature
    • Particle size
    • Mixing

    Amount of Solute in a Solution

    • Weight Percentage (w/w)

      • Weight of solute in 100g of solution

    • Volume Percentage (v/v)

      • Volume of solute in 100 mL of solution

    • Weight/Volume Percentage (w/v)

      • Weight of solute in 100 mL of solution

    • Molarity (M)

      • Moles of solute in 1L of solution

    Acid/Base

    • Acid: releases hydrogen ions
    • Base: accepts hydrogen ions
    • Amphoteric: can do both
    • Acid-base conjugates (acid and its conjugate base) reduce pH change

    Buffer Systems

    • Resist pH changes.
    • Consist of weak acid and its conjugate base, or a weak base and its conjugate acid.

    Regulation of Blood pH

    • Blood pH values usually range between 7.35 and 7.45
    • Bicarbonate buffer system is important
    • Phosphate buffer plays a role
    • Proteins also act as buffers

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    Water, Acids-Bases, and Buffer Systems (2024) PDF

    Description

    This quiz covers key concepts related to water structure, its role as a universal solvent, and the fundamentals of acids, bases, and buffer systems. Understand how these interrelated topics affect biological interactions and processes. Test your knowledge on calculating solution concentrations and the composition of body water.

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