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- reusableconsumed 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+ + Cl-

Bases- electrolytes that absorb H+ from water, or

electrolytes that dissociate to release hydroxide ions (OH-) 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

pH

• pH measures the concentration of hydrogen ions [H+] in a solution.

Acid and Base Concentration

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+].

• Average blood pH = 7.35 - 7.45

• Acidosis = blood pH less than 7.3

• Symptoms include fatigue, disorientation, and difficulty breathing.

Blood

and difficulty breathing.

• Alkalosis = blood pH greater than 7.5

• Symptoms include agitation and dizziness

Chemical components of cells

Organic Vs. Inorganic

Molecules

� Organic moleculeso Compounds with carbon (and usually hydrogen)

o May form macromolecules

o Includes proteins, carbohydrates, lipids, nucleic acidso Includes proteins, carbohydrates, lipids, nucleic acids

� Inorganic moleculeso Compounds that lack Carbon (exception is CO2)

o Usually dissociate in water

• 2/3 of weight in a person

• Transports gasses, nutrients, wastes, ect.Water (H2O)

• Used to release energy from nutrientsOxygen (O2)

Inorganic Substances

• Waste of metabolic reactionsCarbon Dioxide (CO2)

• Na+, Cl-, K+, Ca2+, HCO3-, PO42-Inorganic Salts

End of Section 3, Chapter 2