Chapter 2 Continued Chemical Reactions
Section 3, Chapter 2
Chemical Reactions
All reactions require energy to happen – activation energy • A catalyst reduces the amount of energy needed to initiate a reaction. • Catalysts increase the rate of reactions, but are not consumed by the reaction- reusable
Acids, Bases, and Salts Electrolytes – are substances that dissociate in water to release ions.
Example: NaCl → Na+ + Cl-
Acids - electrolytes that dissociate to release protons (H+) in water Example: HCl→ H+ + ClBases- electrolytes that absorb H+ from water, or electrolytes that dissociate to release hydroxide ions (OH-) in water Examples: NaOH→ Na+ + OH-
Salt – electrolyte formed by the reaction between an acid and base
Acid and Base Concentration pH • pH measures the concentration of hydrogen ions [H+] in a solution. • As pH decreases, [H+] increases – solution is more acidic
Small changes in pH reflect large changes in [H+]. • A change in 1 pH results in a tenfold change in [H+].
Blood • Average blood pH = 7.35 - 7.45 • Acidosis = blood pH less than 7.3 • Symptoms include fatigue, disorientation, and difficulty breathing. • Alkalosis = blood pH greater than 7.5 • Symptoms include agitation and dizziness
Chemical components of cells Organic Vs. Inorganic Molecules Organic molecules o Compounds with carbon (and usually hydrogen) o May form macromolecules o Includes proteins, carbohydrates, lipids, nucleic acids
Inorganic molecules o Compounds that lack Carbon (exception is CO2) o Usually dissociate in water
Inorganic Substances
Water (H2O)
• 2/3 of weight in a person • Transports gasses, nutrients, wastes, ect.
Oxygen (O2)
• Used to release energy from nutrients
Carbon Dioxide (CO2)
Inorganic Salts
• Waste of metabolic reactions
• Na+, Cl-, K+, Ca2+, HCO3-, PO42-
End of Section 3, Chapter 2