Science

• Properties of gases

  • Molecules being separated by weak intermolecular forces of attraction making them distant from each other and freely moving
  • Lower density than solids and liquids
  • No fixed shape and volume
• Gases are compressible
• Gas pressure

  Force exerted by gas molecules colliding with the surfaces of objects
• Boyle's Law


  1. As the pressure increases the volume of the gas decreases

  2. As the pressure decreases the volume increases

  3. If there is a decrease in the volume of gas, air molecules will have less space to move

  4. Molecules will strike the walls of the container more often

  5. Results in greater pressure

  
• Applications of Boyle's Law


  • Chest respirator
  • Sphygmomanometer
• Chest respirator


  • Machine used in the treatment of patients with respiratory difficulties
  • When the pressure inside the respirator is decreased, the air in the lungs expands, forcing the diaphragm down
  • When the pressure of the respirator is increased, the volume of air in the lungs is decreased, allowing the diaphragm to move upward again
  • Alternate increase and decrease in pressure enables the patient to breathe even though they cannot control the movement of the diaphragm muscles
• Sphygmomanometer


  • Device used to measure blood pressure
  • When the rubber bulb is squeezed, the volume of air in that bulb is decreased and its pressure is increased
  • This increased pressure is transmitted to the cuff

  
• Charles's Law


  • The volume and temperature of a fixed amount of gas are proportional at constant pressure
  • Doubling the temperature of a gas doubles its volume
  • Halving the temperature of a gas halves its volume

  
• Charles's Law Formula


  V = kT, where T is absolute temperature, V is volume, and k is a non-zero constant
• The graph of volume versus pressure shows the linear relationship, and the line points toward the origin, although a gas could never reach it because it would change into a liquid or solid first

  
• Organic molecules


  Carbon-containing compounds, present mostly in living things
• Monomers


  Individual units, one part
• Polymers


  Long chain of monomers

  
• Biomolecules


  Carbon-containing compounds which are essential to life
• 4 Biomolecules


  • Carbohydrates
  • Proteins
  • Lipids
  • Nucleic acids
• Carbohydrates


  • Made from aldehydes and ketones containing numerous hydroxyl groups
  • Contain carbon, hydrogen, and oxygen
  • General empirical structure: (CH2O)n
  • The most abundant organic molecules in nature
  • Referred to as "saccharides"
  • Soluble in water and sweet in taste are called "sugars"
• Functions of carbohydrates


  • Used as accessible energy to fuel cellular reactions
  • Chief energy source (4kcal/gram) for all living beings
  • Instant sources of energy in many animals
  • Serve as energy stores, fuels, and metabolic intermediates
  • Stored as glycogen in animals and starch in plants
  • Stored carbohydrates act as an energy source instead of proteins
  • Intermediates in the biosynthesis of fats and proteins
  • Aid in the regulation of nerve tissue and the energy source for the brain
  • Important constituent of connective tissues in animals
  • Rich in fiber content help to prevent constipation
• Proteins


  • Polymers of amino acids
  • Have many functions in the body
  • Structural materials in hair, nails and connective tissues
  • Enzymes are proteins that act as biological catalysts
  • Made up of the elements carbon, hydrogen, oxygen, nitrogen and sulfur
  • Second most common molecules found in the human body (after water)
  • Make up about 10% to 20% of the mass of a cell

  
• Types of Amino Acids in Proteins


  • Essential
  • Non-Essential
• Lipids


  • Water insoluble molecules (hydrophobic or water-fearing)
  • Composed of carbon, hydrogen and oxygen
  • Used for storing energy for later use
  • Also found in hormones and cell membrane components
  • The most abundant are the fats and oils, also called triglycerides
  • Fats and oils are triglycerides that come from the combinations of glycerol and three fatty acids
  • Waxes are lipids that come from the combinations of a long-chain alcohol and a fatty acid
  • Steroids are another class of lipids whose molecules are composed of fused rings of atoms, the most important steroid is cholesterol
  • Lipids are the polymers of fatty acids that contain a long, non-polar hydrocarbon chain with a small polar region containing oxygen
• 3 Types of Lipids


  • Triglycerides
  • Steroids
  • Phospholipids
• Nucleic Acids


  • Long chains of polymers consisting of simpler units or monomers
  • There are two kinds: DNA (deoxyribonucleic acid) and RNA (ribonucleic acid)
  • DNA found mainly in the cell nuclei contains the genetic information that codes for the sequences of amino acids in proteins
  • RNA is found in many places in the cell and carries out the synthesis of proteins
  • The monomers of nucleic acids are nucleotides, made up of a five-carbon sugar (pentose), a phosphate group, and a ring-shaped base containing nitrogen

  
• Law of Conservation of Mass

  • Mass is conserved in a chemical reaction
  • The total mass of the reactants is equal to the total mass of the products
  • No new atoms are created or destroyed, there was only grouping or regrouping (rearrangement) of atoms
• In some cases, the chemical equation is not always written in the state of balance, meaning the number of each element in both sides of the equation is not the same
• A balanced equation shows the same number of each element on both sides of the equation