science 2nd quarter

Louis Pasteur

• Proposed Germ Theory: microorganisms cause disease.

• Developed pasteurization to prevent contamination.

• Emphasized laboratory safety and sterile techniques.

Antoine Lavoisier

• Formulated the Law of Conservation of Mass: mass is neither created nor destroyed in a chemical reaction.

• Important in explaining chemical reactions accurately.

John Dalton

• Proposed Atomic Theory:

o Matter is made of atoms.

o Atoms cannot be created or destroyed in chemical reactions.

o Elements combine in fixed ratios.

Robert Boyle

• Known for Boyle’s Law: relationship between gas pressure and volume.

• Helped establish chemistry as a modern science.

Rosalind Franklin

• Took Photo 51, which provided key evidence for the double-helix structure of DNA.

Ernest Rutherford

• Discovered the nucleus using the gold foil experiment.

decomposition

when a compound breaks down into 2 or more simpler substances

Acid–Carbonate Reactions

Acid + Carbonate → Salt + Water + Carbon Dioxide

e.g., vinegar + baking soda, antacid tablets neutralizing stomach acid

• Importance:

o Relieves acidity

o Produces harmless CO2 gas

Surfactants (Sodium Lauryl Sulfate, SLS)

• Found in soaps, shampoos, detergents.

• Reduce surface tension.

• Trap grease in micelles, allowing it to be washed away.

FDA (Food and Drug Administration)

• Ensures safety of food, drugs, cosmetics, and personal care products.

DTI (Department of Trade and Industry)

• Ensures proper labeling of products.

• Protects consumer rights and safety.

DENR (Department of Environment and Natural Resources)

• Regulates disposal of chemical waste.

• Protects the environment and public health.