Presentation on theme: "Chapter 2: The Chemistry of Life Section 1: The Nature of Matter"— Presentation transcript:
1 Chapter 2: The Chemistry of Life Section 1: The Nature of Matter CCS BiologyMr. Bogusch
2 Atoms Atoms – basic units of matter Atoms are made of three parts Proton – positively charged subatomic particleNeutron – subatomic particle with no chargeElectron – negatively charged subatomic particle1/1840 mass of a protonAn atoms positive and negative charges even each other out which make the atom neutral
6 Elements and IsotopesIsotope – atom of the same element that have different number of neutronsMass Number – total number of protons and neutronsRadioactive Isotope – nuclei are unstable and break down at a constant rate over time.UsesRadiometric datingDetect and treat cancer
7 Chemical CompoundsCompound – substance formed by the chemical combination of two or more elements in definite proportionsChemical Formula ExamplesNaCL, H2O
8 Chemical CompoundsThe characteristics of compounds are usually different form the individual elements it is made ofFor ExampleH2O – Water – if you combine hydrogen gas and oxygen gas it can be explosive!NaCl – Salt – sodium chloride – salt is essential to all living thingsNa – Sodium – silver colored metal soft enough to cut with a knife that reacts explosively with waterCl – Chlorine – poisonous gas used in WWI – chemical warfareHydrogen and Oxygen BalloonsSodium and Water
9 Chemical BondsIonic Bond – formed when 2 or more electrons are transferred from one atom to anotherIons – atoms that gain or lose an electronFor exampleNa+ + Cl --- → NaClPositively charged + negatively charged = neutral charge
11 Chemical Bonds Covalent Bond – formed when atoms share electrons Molecule – atoms joined together by covalent bondsFor example: H2O
12 Chemical BondsVan der Waals Forces – a weak chemical attraction between oppositely charged regions of nearby moleculesFor Example: H2O, Tokay gecko
13 Chapter 2: The Chemistry of Life Section 2: Properties of Water
14 The Water MoleculeFound in liquid form over most of the Earth’s surfaceLike most molecules, Water is neutralH2O has 10 protons (positive) and 10 electrons (negative)The protons and electrons balance each other out!
15 The Water MoleculePolarity – a molecular with an uneven distribution of chargeOxygen has 8 protons which attract electrons strongly, as a result most of water electrons are found near the oxygen atom making that side of the atom partially negative charged
16 The Water MoleculeHydrogen Bonding - that attraction between a hydrogen atom with a partially positive charge with another atom with a partial negative chargeBecause of their partial positive and negative charges, polar molecules can attract each other.Because water is a polar molecule, it is able to form multiple hydrogen bonds, which account for many of water’s special properties.
18 The Water MoleculeCohesion –attraction between molecules of the same substanceWater can attract itself forming “beads” of waterCohesion also produces surface tensionWater molecules hydrogen bonds have a certain amount of strengthFor example – spiders that can walk on water
20 The Water MoleculeAdhesion – the attraction between molecules of different substancesFor example: water on glass
21 The Water Molecule Heat Capacity Since there are multiple hydrogen bonds between water molecules it takes a large amount of energy to cause those molecules to move fast, which raises the temperature.For example: large lakes and oceans retain heat even though the air will become colder. This protects against drastic change in temperature
22 Solutions and Suspensions Mixture – a material composed of two or more elements or compounds that are physically mixed together but not chemically combined.
23 Solutions and Suspensions Two types of mixtures that re combined with water are solutions and suspensionsSolutions- a substance that is evenly distributed in waterSolute – the substance that is dissolvedSolvent (water)– the substance in which the solute dissolvesWater’s polarity gives it the ability to dissolve both ionic and other polar moleculesSuspension – mixtures of water and nondissolved material
25 Acids, Bases, and pH Water molecules split to form ions pH Scale – indicates the concentration of H+ ions in a solutionRange 0 – 14Acids < pH of 7 (contain a high concentration of H+ ions)Bases > pH of 7 ( contain a high concentration of OH- ions and a low concentration of H+ ions)Neutral = 7 (contain no H+ ions or OH- ions “theoretically”)