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Section 2a. Levels Chemical Cells Tissue Organ Organ system Organism Today we are working on…

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Presentation on theme: "Section 2a. Levels Chemical Cells Tissue Organ Organ system Organism Today we are working on…"— Presentation transcript:

1 Section 2a

2 Levels Chemical Cells Tissue Organ Organ system Organism Today we are working on…

3 Matter The “stuff” of the universe Anything that has mass and takes up space States of matter – Solid – has definite shape and volume – Liquid – has definite volume, changeable shape – Gas – has changeable shape and volume

4 Energy The capacity to do work (put matter into motion) Types of energy – Kinetic – energy in action – Potential – energy of position; stored (inactive) energy

5 Forms of Energy Chemical Chemical – stored in the bonds of chemical substances Electrical Electrical – results from the movement of charged particles Mechanical Mechanical – directly involved in moving matter Radiant Radiant or electromagnetic – energy traveling in waves (i.e., visible light, ultraviolet light, and X rays)

6 Energy Form Conversions Energy is easily converted from one form to another During conversion, some energy is “lost” as heat Energy is never created or destroyed

7 Composition of Matter Elements are the fundamental units of matter Elements – unique substances that cannot be broken down by ordinary chemical means

8 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

9 Major Elements of the Human Body There are about 120 known elements – 92 occur in nature – the rest are man-made 96% of the body is made from four elements - Know these – Oxygen (O) Carbon (C) Hydrogen (H) Nitrogen (N)

10 Lesser 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)

11 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

12 Composition of Matter Each Element is composed of Atoms Atoms = more or less identical building blocks for each element Atomic symbol = one or two letter chemical shorthand for each element Carbon CNitrogen N Oxygen OCalcium Ca Hydrogen HSodium Na

13 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

14 Atomic Structure Electrons are found orbiting the nucleus – Electrons – have a negative charge and 1/2000 the mass of a proton (0 amu)

15 Models of the Atom Nucleus – Prontons (p + ) – Neutrons (n 0 ) Outside of nucleus – Electrons (e - ) Figure 2.1

16 Models of the Atom Planetary Model – electrons move around the nucleus in fixed, circular orbits Figure 2.1

17 Models of the Atom Orbital Model – regions around the nucleus in which electrons are most likely to be found Figure 2.1

18 Identification of Elements Atomic number – – equal to the number of protons that the atoms contain Mass number – – equal to the mass of the protons and neutrons – sum of the protons and neutrons

19 Identification of Elements Atomic weight – – average of the mass numbers of all isotopes – Close to mass number of most abundant isotope – Atomic weight reflects natural isotope variation

20 Isotopes Isotope – atoms with same number of protons but a different number of neutrons Radioisotopes – atoms that undergo spontaneous decay called radioactivity

21 Radioactivity Rodioisotope – – Heavy isotope – Tends to be unstable – Decomposes to more stable isotope Radioactivity – Process of spontaneous atomic

22 Identification of Elements Figure 2.2

23 Identification of Elements Isotopes of Hydrogen Figure 2.3

24 Molecules and Compounds Molecule – two or more atoms held together by chemical covalent bonds Compound – two or more different kinds of atoms chemically bonded together in ionic bonds Next time we will talk how these are chemically bonded

25 Mixtures and Solutions Mixtures – two or more components physically intermixed (not chemically bonded) 3 basic types – Solutions – Colloids – Suspensions

26 Solutions Solutions – homogeneous mixtures of components – Solvent – substance present in greatest amount – Solute – substance(s) present in smaller amounts May be gases, liquids, or solids

27 Solutions Water is the body’s chief solvent Most solutions in the body are true solutions containing gases, liquids, or solids dissolved in water – True solutions are usually transparent

28 Concentration of Solutions True solutions are described in terms of their concentration (percent or molarity) Percent, or parts per 100 parts Molarity, or moles per liter (M)

29 Concentration of Solutions To make a one-molar solution of glucose – weigh out 1 mole of glucose and add enough water to make 1 liter of solution A mole of an element or compound is equal to its atomic or molecular weight (sum of atomic weights) in grams

30 To find molecular weight of glucose C 6 H 12 O 6 – Glucose has 6 carbon, 12 hydrogen, & 6 oxygen atoms To compute molecular weight of glucose, look up the atomic weight of carbon, hydrogen and oxygen on a periodic table. Molecular weight of glucose is

31 Atom# of atomsXAtomic weight = C6X12.033=72066 H12X1.008= O6X15.999=

32 Avogadro’s Number One mole of any substance always contains exactly the same number of solute particles 6.02 X So whether you weigh out 1 mole of glucose (180g) or water (18g) or methane (16g) or any other substance you will always have 6.02x10 23 molecules of that substance

33 Colloids and Suspensions Colloids, or emulsions, are heterogeneous mixtures whose solutes do not settle out Suspensions are heterogeneous mixtures with visible solutes that tend to settle out

34 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

35 Quiz 1a over these lecture notes Study guide check pages 24-28

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