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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Lecture 3 Basic Chemistry
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Matter
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Matter The “stuff” of the universe Anything that has mass and takes up space Weight and mass. States of matter Solid – has definite shape and volume e.g. bone Liquid – has definite volume, changeable shape e.g. blood Gas – has changeable shape and volume e.g. air
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Energy The capacity to do work or put matter into motion Energy has no mass,does not take up space.It can be measured by effect on matter. Types of energy Kinetic – energy in action Potential – energy of position; stored (inactive) energy
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Kinetic energy performs work by transferring motion to other matter – For example, water moving through a turbine generates electricity – Heat, or thermal energy, is kinetic energy associated with the random movement of atoms Copyright © 2009 Pearson Education, Inc.
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings An example of potential energy is water behind a dam – Chemical energy is potential energy because of its energy available for release in a chemical reaction Copyright © 2009 Pearson Education, Inc.
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Energy Form Conversions Energy is easily converted from one form to another During conversion, some energy is “lost” as heat e.g. body temperature, lit bulb.
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
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5.11 Two laws govern energy transformations Energy transformations within matter are studied by individuals in the field of thermodynamics – Biologists study thermodynamics because an organism exchanges both energy and matter with its surroundings Copyright © 2009 Pearson Education, Inc.
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings 5.11 Two laws govern energy transformations It is important to understand two laws that govern energy transformations in organisms – The first law of thermodynamics—energy in the universe is constant – The second law of thermodynamics—energy conversions increase the disorder of the universe – Entropy is the measure of disorder, or randomness Copyright © 2009 Pearson Education, Inc.
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Fuel Gasoline Energy conversion in a cell Energy for cellular work Cellular respiration Waste productsEnergy conversion Combustion Energy conversion in a car Oxygen Heat Glucose Oxygen Water Carbon dioxide Water Carbon dioxide Kinetic energy of movement Heat energy
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Forms of Energy Chemical – stored in the bonds of chemical substances e.g.ATP Electrical – results from the movement of charged particles e.g. nerve impulse, Mechanical – directly involved in moving matter Radiant or electromagnetic – energy traveling in waves (i.e., visible light, ultraviolet light, and X-rays)
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Composition of Matter Elements – unique substances that cannot be broken down by ordinary chemical means Atoms – more-or-less identical building blocks for each element Atomic symbol – one- or two-letter chemical shorthand for each element
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Properties of Elements Each element has unique physical and chemical properties Physical properties – those detected with our senses Chemical properties – pertain to the way atoms interact with one another
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings What are the major elements of our body
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Major Elements of the Human Body Oxygen (O) Carbon (C) Hydrogen (H) Nitrogen (N)
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Lesser and Trace Elements of the Human Body Lesser elements make up 3.9% of the body and include: Calcium (Ca), phosphorus (P), potassium (K), sulfur (S), sodium (Na), chlorine (Cl), magnesium (Mg), iodine (I), and iron (Fe)
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Lesser and Trace Elements of the Human Body Trace elements make up less than 0.01% of the body They are required in minute amounts, and are found as part of enzymes
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
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Atomic Structure The nucleus consists of neutrons and protons Neutrons – have no charge and a mass of one atomic mass unit (amu) Protons – have a positive charge and a mass of 1 amu Electrons are found orbiting the nucleus Electrons – have a negative charge and 1/2000 the mass of a proton (0 amu)
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Models of the Atom Planetary Model – electrons move around the nucleus in fixed, circular orbits Orbital Model – regions around the nucleus in which electrons are most likely to be found
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Models of the Atom Figure 2.1
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Magnesium Lithium Hydrogen Third shell First shell Second shell Sodium Beryllium Aluminum Boron Silicon Carbon Phosphorus Nitrogen Sulfur Oxygen Chlorine Fluorine Argon Neon Helium
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Identification of Elements Atomic number – equal to the number of protons Mass number – equal to the mass of the protons and neutrons Atomic weight – average of the mass numbers of all isotopes
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Identification of Elements Isotope – atoms with same number of protons but a different number of neutrons Radioisotopes – atoms that undergo spontaneous decay called radioactivity
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Identification of Elements: Atomic Structure Figure 2.2
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Identification of Elements: Isotopes of Hydrogen Figure 2.3
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
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Why are the number of neutrons so important??? Isotopes = variant forms of the same element Different # of neutrons Different mass number Naturally occurring Virtually the same chemical properties Unstable nuclei spontaneously release energy ~ radiation
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Radioactive Isotopes Release detectable signals, so they can be used in tracing and tracking portions of atoms or molecules Medical Applications: Treatment (ex: cancer) Diagnosis (tracers used in scans) Sterilization (ionizing radiation) Research Dating fossils or items (Carbon 14 dating)
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Carbon 14 dating 99% of all carbon is C 12 (6 protons, 6 neutrons) 1% of all carbon is either: C 13 (6 protons and 7 neutrons) Or C 14 (6 protons and 8 neutrons) Scientists date materials based on the ratio of C12:C13:C14 and the mathematical decay rate
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Molecules and Compounds Molecule – two or more atoms held together by chemical bonds Compound – two or more different kinds of atoms chemically bonded together
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Mixtures and Solutions Mixtures – two or more components physically intermixed (not chemically bonded) Solutions – homogeneous mixtures of components Solvent – substance present in greatest amount Solute – substance(s) present in smaller amounts
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Concentration of Solutions Percent, or parts per 100 parts Molarity, or moles per liter (M) A mole of an element or compound is equal to its atomic or molecular weight (sum of atomic weights) in grams
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Colloids and Suspensions Colloids (emulsions) – heterogeneous mixtures whose solutes do not settle out Suspensions – heterogeneous mixtures with visible solutes that tend to settle out
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Mixtures Compared with Compounds No chemical bonding takes place in mixtures Most mixtures can be separated by physical means Mixtures can be heterogeneous or homogeneous Compounds cannot be separated by physical means All compounds are homogeneous
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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Thank you
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