MA

Solute Concentration and Acid-Based Chemistry

Objectives

  • Preform common concentration and dilution calculations

  • Recognize acid/base behavior and interpret pH

Why it matters

  • ABG (Arterial Blood Gas interpretation:

    • Acid-base balance depends on ions (H+,HCO-3). Knowing equivalents helps you understand how small ion changes pH shifts. 

  • Ventilator management:

    • Patients on ventilators often get IV fluids. Orders are written

  • Nebulizer solution and meds:

    • Treatments (like hypertonic saline) depend on concentration and osmotic effects you must know how solutes and solvents work.

  • Critical care decisions

    • Electrolyte distrubrances (hyperkalemia, hypontremia) affect heart rhythm and muscle function, including the muscles of breathing.

Measuring the amount of a substance.

  • Actual weight

    • this is the straight weight of the chemical in grams (g) or milligrams

  • Combining force (equivlant wieght)

    • more common in medicine

      • Instead fo just weight it measures how much of the substance will chemically react or combine with other substances.

      • Units: gram equivalnt (geq) or milliequivalent (mEq).

Electrolytes

  • Are often measured in millliequivalents becaue the charge affects body fluid balance not just the raw grams

Gram Atomic weight

  • THe weight of one mole of the substance in grams

  • If a particle carries more charges (higher valence) each gram gives more charge so the gram equivalent weight is smaller. 

  • Nebulized sodium chloride (saline) is a perfect example where molecular weight and equivalent really matter.

    • Nebulized saline dissolved

Valence

  • The number of charges or replaceable hydrogens

Ways to measure a solution

  • Ratio solution: show part of solute (stuff dissolved) to total solution. 

    • 1:100 mean 1 gram of drug in 100 mL of total solution

  • Weight per Volume (W/V)- grams of solute per 100 mL of solution. 

  • Percent (%) solution: just another way to saw W/V

  • Molal Solution (mol/kg): moles of solute per kilogram of solvent

    • think of this as measuring by weigt of liquid

  • Molar solution (mol/L) : moles of solute per liter of soulution.

  • Normal solution (gEg/L) grams of equivalent per leiter

    • uses electrical charge of ions (like Na+ or Cl-)

Dilution calculation:

  • V1C1=V2C2

    • V1= Starting Volume

    • C1= Starting concentration

    • V2= final volume

    • C2+ Final concentration

    • Always change percentage to decimals

RT’s must:

  • Choose the right concentration

  • Choose the right amount

  • Verify it’s safe (per patient)

  • Verify its for the right indication

  • Be aware of contradictions and side effects. 

Acids:

  • Give away H+ ions  or grab electrons

    • HCl donates 1 H+ → strong stomach acid

    • H2SO4 (sulfuric acid): donates 2 H+ → battery acid

Bases:

  • Give OH ions (hydroxide or can neutralize acids by grabbing H+

    • NaOh  give OH- → strong cleanre

    • Ammonia grams and and forms NH4+

    • Protiens (hemoglobin): can hold H+ without releasing OH- → important in blood pH. 

Pure water

  • equal amounts of hydrogen ions and hydroxide ions

    • hase more H+ or less OH- than water is acidic

    • if it has less H+ and more OH_, than its more alkaline/basic (like baking soda)