Science 4th quarter

• Kinetic Molecular Theory


  Describes how gases behave
• Properties of gas


  • No definite shape
  • No definite volume
  • Takes the shape and volume of its container
• Gas


  • Can be compressed to a smaller volume resulting in density
  • Compressibility: measure of how much the volume of matter decreases under pressure
  • Fills its containers uniformly
  • Exerts pressure
  • Diffuses and mixes with one another to form a homogeneous mixture
  • Pressure depends on temperature
• • Gases are colorless
  • Gases have very low density and viscosity
• Fundamental properties of gases

  • Pressure (P)
  • Volume (V)
  • Temperature (T)
  • Amount of gas (n)
• Pressure (P)


  • Ratio of the applied force to a certain contact surface area
  • Units: atmosphere (atm), mmHg, pascal (Pa)
• Volume (V)


  • Space occupied by matter or by the gas
  • Units: Liter (L), Milliliter (mL)
• Temperature (T)


  • Measure of the average kinetic energy of a body
  • Units: Celcius (C), Kelvin (K)
• Quantity (n)


  • Amount of gas
  • Units: Grams (g), Moles (n)
• Amount of gas, volume and the temperature are factors that affect gas pressure
• Assumptions of the Kinetic Molecular Theory

  • Gases are composed of very small particles called atom or molecules
  • Distances between gas particles are very great that the volume of the gas is mostly empty space
  • There are no opposing or attractive forces between gas particles
  • Gas particles are in constant random motion
  • Collisions between gas particles or with the walls of the containers are perfectly elastic, that is, no energy of motion is lost
  • The kinetic energy of the particles depends on the temperature of the gas (higher KE, higher temperature; lower KE, lower temperature)
• Ideal Gas


  Theoretical gas that follows all the conditions standard pressure and temperature
• Pressure


  Every time you inflate a balloon, the gas particles inside collide against the inside surface of the balloon and exert an outward push or force called pressure
• Atmospheric Pressure


  • The gases of the atmosphere also exert pressure on everything they are in contact with
  • The standard atmospheric pressure at sea level is at 1 atm or 760 mmHg or 760 torr
• Standard Temperature Atmosphere (STP)


  • Standard condition of temperature and pressure is known as STP
  • Universal value of STP is at 1.0 atm (pressure) and 0 degree Celcius (temperature)
• Boyle's Law


  1. When you squeeze a balloon, the confined gas can be compressed to a smaller volume and the pressure of the gas increases

  2. The volume of a fixed quantity of a gas is inversely proportional to pressure

  3. Formula: P1V1 = P2V2
• Charles' Law


  1. At constant pressure, the volume of gas increased when heated and decreased when cooled

  2. The volume is directly proportional to its temperature

  3. Formula: V1T2 = V2T1

  
• Gay-Lussac's Law


  1. The pressure of a gas is directly related to its kelvin temperature

  2. Formula: P1T2 = P2T1

  3. Temperature degree Celcius to Kelvin = 273.15

  
• Combined Gas Law


  1. Single relationship that combines pressure, volume, and temperature

  2. Formula: P1V1T2 = P2V2T1

  
• Four Biomolecules


  • Carbohydrates
  • Lipids
  • Proteins
  • Nucleic Acids
• Carbohydrates


  • Carbs or sugar molecules
  • One of the three main nutrients found in foods and drinks
  • Main source of body energy
  • Body breaks down carbohydrates into glucose
  • Excess glucose is stored as glycogen or starch
• Types of Carbohydrates


  • Monosaccharides (simple, soluble, sweet, energy source, good flavor)
  • Disaccharides (two monosaccharides linked, simple, soluble, sweet, transport form)
  • Polysaccharides (complex, composed of large numbers of monosaccharide units, insoluble, tasteless, storage form)
• Monosaccharides


  • Glucose
  • Fructose
  • Galactose
• Disaccharides


  • Lactose
  • Sucrose
  • Maltose
• Polysaccharides


  • Cellulose
  • Glycogen
  • Starch
• Disaccharides are too large to pass through cell membranes, they are broken down to glucose and fructose, which are small enough to be absorbed by cells as nutrients
• • Too much carbohydrate intake can cause many diseases but mostly obesity
  • Deficiency intake can cause many diseases but mostly malnutrition
• Lipids


  • Substances with very different composition and structures compared with carbohydrates
  • Insoluble in water but soluble in nonpolar solvents (hydrophobic)
  • Waxy, oily, greasy substances in plants and animals
  • Fats and oils are rich in energy and low densities
  • Used as structural components in the formation of cellular membranes

  
• • Lipid molecules are found in fatty foods such as meat, butter, cheese, peanut butter, margarine and oil
  • The waxes you use to polish your car and the grease you use for your bike are also lipids
• Roles of Lipids


  • Excess energy is stored as lipid molecules
  • Form the membranes that surround cells and many of their parts
  • Insulators to prevent loss of body heat
• Structure of Lipids


  • Glycerol (sugar containing 3 hydroxyl groups)
  • Fatty acids (long chains of carbon atoms with a carboxyl group at one end)
  • Triglycerides (3 fatty acids)
  • Saturated fats (unhealthy, straight chains, single bonds)
  • Unsaturated fats (healthy, bent chains, double bonds)
  • Phospholipids (contain phosphorus, 2 fatty acids)
  • Waxes (long chains of fatty alcohols or esters)
  • Steroids (including cholesterol)

  
• Protein


  • Polymers made up of several amino acid monomers
  • Most important biomolecule
  • Protein foods are eggs, milk, meat, fish, and beans
  • Help build and repair body parts
• Structure of Protein


  • Contains carbon, hydrogen, oxygen, and nitrogen
  • Nitrogen comprises about 15% of the mass of a protein molecule
  • More than 700 types of amino acids, but only 20 are used by human cells
  • Amino acids are connected by peptide bonds
• Roles of Proteins


  • Structural (provide strength and shape)
  • Contractile (responsible for muscle movement)
  • Storage (source of nitrogen for embryos)
  • Defensive (protect against diseases)
  • Transport (carry substances like hemoglobin)
  • Hormonal (coordinate body activities)
  • Receptor (enable cells to respond to stimuli)
  • Catalytic (enzymes that speed up reactions)
• Excessive protein intake can strain the kidneys, lead to dehydration, affect bone health, cause digestive issues, and create nutrient imbalances. Moderation and balance are key for maintaining overall health, as protein is essential but too much can have adverse effects
• Insufficient protein intake can lead to muscle loss, malnutrition, and other health problems
• Hormonal Proteins


  Helps coordinate activities in the body (example, insulin; regulates the sugar concentration in the blood)
• Receptor Proteins


  Enable the body cells to respond to chemical stimuli
• Catalytic Proteins


  Called enzymes, most specialized proteins, it speeds up reactions without affecting themselves and the products. The structure of an enzyme is crucial for its effectiveness as a catalyst
• Excessive protein intake can strain the kidneys, lead to dehydration, affect bone health, cause digestive issues, and create nutrient imbalances. Moderation and balance are key for maintaining overall health, as protein is essential but too much can have adverse effects. Consulting with a healthcare provider or dietitian can help determine appropriate protein intake