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BASIC CHEMISTRY Unit 1. Scientific Method Is the process employed by scientist to support or reject an idea, by accumulating data, and testing the data.

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Presentation on theme: "BASIC CHEMISTRY Unit 1. Scientific Method Is the process employed by scientist to support or reject an idea, by accumulating data, and testing the data."— Presentation transcript:


2 Scientific Method

3 Is the process employed by scientist to support or reject an idea, by accumulating data, and testing the data under conditions which are controlled in ways to give credible results. If an idea or hypothesis withstands substantial independent testing it becomes a theory, then a law or principle.

4 Scientific Method This site has a nice explanation and a quiz for you to test yourself od.html od.html

5 States Of Matter Solid  Definite shape and volume. Liquid  Takes shape of container; definite volume. Gas  Takes shape of container. (compressible).

6 Properties Physical  What a substance is.  Color, density, odor, solubility in water.  Density  Weight per unit volume. Chemical  What a substance does  +/- Reactivity with water or air.  +/- Burning in a flame.

7 Physical vs Chemical Changes Physical change: Although some extensive properties (like shape, phase, etc.) of the material change, the material itself is the same before and after the change. The change can be “undone.” Chemical change: The atoms have been altered. What was there at the beginning is no longer the same. Chemical changes cannot be undone. Ice melting is an example of a physical change Steel rusting is an example of a chemical change

8 Energy Kinetic Energy The energy of motion Potential Energy Stored energy

9 Conservation Laws Matter is neither created or destroyed, only arranged from one form to another. Energy is neither created or destroyed, only changed from one form to another.  Potential  Kinetic  Heat. Click on the image to see an animation

10 Elements Substances which cannot be broken into simpler substances by ordinary means. Are homogeneous in composition  the same throughout. Each element represented by a symbol. O = Oxygen C = Carbon AU = Gold.

11 Periodic Table Another version at

12 Atomic Structure Atoms are electrically neutral Composed of protons, neutrons & electrons

13 The Nucleus of the Atom Protons Positive charge Number of protons is the atomic # All atoms of same element have same atomic # Neutron No charge ie neutral Same mass as a proton located in nucleus Number of protons + neutrons = atomic weight Number of Protons Number of Protons + Neutrons

14 Isotopes Different # of neutrons than normal, i.e., different atomic weight. Normal Carbon 6 protons + 6 neutrons Atomic Mass = 12 Carbon 14 Isotope 6 protons + 8 neutrons Atomic Mass = 14

15 Electrons 1/1837, the mass of a proton orbit the nucleus Directly involved in chemical reactions Determines the chemical property of the atom Negative charge Equal in number to the number of protons Arranged in energy levels or shells around nucleus; 1st shell holds two—all others hold eight Happiness is a full outer shell

16 Atomic Structure

17 Electron Arrangement Arranged in energy levels or shells around nucleus; 1st shell holds two—all others hold eight Happiness is a full outer shell Atoms will share, give away or pick up electrons to achieve a full outer shell

18 Electron Arrangement For example: Carbon  Atomic Number 6, Atomic Mass 12  This tells us there are 6 protons (atomic number)  6 neutrons (atomic mass – atomic number)  And 6 electrons (equal to the number of protons)  The first shell holds a maximum of 2  The other 4 will be in the second shell  So Carbon has 4 electrons in its outer shell

19 Electron Arrangement For example: Cobalt (Co)  Atomic Number 27, Atomic Mass 58.93 ( round up to 59 )  This tells us there are 27 protons (atomic number)  32 neutrons (atomic mass – atomic number)  And 27 electrons (equal to the number of protons)  2 in the first shell  Remember all other shells hold a maximum of 8  8 in the second, 8 in the third, 8 in the fourth  We still have one left so that 1 electron is in the fifth  Cobalt has 1 electron in its outer shell

20 Electron Arrangement Now would be a good time for you to work on the Periodic Table Assignment!

21 Atomic Bonding Ionic Bonding Results from the transfer of electrons Atoms gain/lose electrons. Results in ions  Atom with a charge. The charge difference holds the resulting molecule together Click on the image to see an animation

22 Atomic Bonding Covalent Bonding Results from a sharing of electrons between two atoms. Each atom provide an electron The Shared electron pair orbits both nuclei this is what keeps the molecule together Larger nuclei will hog the shared electrons from smaller nuclei Click on the image to see an animation

23 Atomic Bonding Hydrogen Bond Special bond—very weak Bond between molecules NOT between atoms Results from a covalent bond involving hydrogen Shared electron spends more time around the bigger nucleus of the Oxygen atom This leaves the hydrogen end with a net positive charge & the Oxygen end with a net negative. A polar molecule due to the charge difference from one end of the molecule to the other. Covalent Bond Between Oxygen and Hydrogen Between two Water molecules

24 Compounds Combination of elements. Can be separated into their parts by chemical means. Homogeneous in composition. Definite composition Have different properties than their parts  Example: Oxygen +Hydrogen= H 2 O water.  Oxygen and Hydrogen at room temperature are gasses  Neither conduct electricity  Water is a liquid at room temperature and does conduct electricity

25 Mixture Combination of substances Can be separated by physical means No set composition Heterogeneous in composition Parts retain their own character  Example: Italian Salad Dressing  The vinegar and oil can be mixed together with spices but they can be separated from one another

26 Macromolecules: Proteins Compound of amino acids joined together. Each protein has a definite structure.  Primary—linear sequence of amino acids  Secondary-Initial folding to sequester hydrophobic  (water hating) amino acids.  Alpha Helix  Beta Pleated Sheet  Tertiary—Complex folding to created final 3D shape

27 Macromolecules: Proteins Protein Structure Click on the image to see an animation

28 Macromolecules: Proteins Denaturation  To destroy the shape of a protein  Heat, ph, salt concentrate on  Maybe reversible or not  Cook an egg: the heat denatures the albumin protein in egg white

29 Macromolecules: Carbohydrates Carbohydrates Sugars, Starches, Cellulose All contain carbon, hydrogen, & oxygen in a 1:2:1 ratio Glucose C6H12O6 Monosaccharide: Single Sugar, glucose. Disacharide: Double Sugar, sucrose

30 Macromolecules: Carbohydrates Polysacharride : Many sugar molecules joined together Starch  Plant form of energy storage.  Insoluble in water.  Digestible by animals.  Detected by iodine. Celluose  wood, cotton, paper;  insoluble in water;  not digestible by animals. Glycogen  Animal form of energy storage

31 Macromolecules: Nucleic Acids Information storage DNA: DeoxyriboNucleic Acid) Organism’s instructions for assembly Double stranded Located in nucleus BASES AdenineGuanine ThymineCytosine

32 Macromolecules: Nucleic Acids RNA: RiboNucleic Acid Information Use, daily operation of organism. Single stranded Made in nucleus, exported for work throughout cell BASES  AdenineGuanine  Uracil Cytosine

33 Macromolecules: Lipids / Fats Insoluble in water. Combination of fatty acids and glycerol. Reserve energy storage. Make up cell membranes and some hormones

34 Macromolecules: Lipids / Fats Saturated All carbon atoms linked by single bond. “Saturated with hydrogen” Solid at room temp Most of the animal fats  responsible for increasing the amount of cholesterol Unsaturated At least one double bond between 1 pair of carbon atoms. Liquid at room temperature Most vegetable fats

35 Enzymes Biological catalyst. Increases the rate of chemical reaction. Lowers the activation energy required for reaction. All enzymes are proteins. Have specific active site to bind to substrates. These active sites are created by the 3D structure of the protein. What would you expect if an enzyme was subjected to extreme heat? Click on the image to see an animation

36 Acids Donate H+ ions to solution Can be in solid or liquid form Sour taste The more H+ ions released the stronger the acid Common Acids  HCl Hydrochloric (in stomach)  H 2 SO 4 Sulfuric (battery acid)  HNO 3 Nitric (Medical Testing)  H 2 CO 3 Carbonic (Soda)

37 Bases Donate OH-, hydroxide ions to solution Slippery feel Bitter taste Common Bases  NaOHSodium Hydroxide (Drain cleaner)  NH 4 OH Ammonium Hydroxide (Cleaning)  NH 3 Ammonia (Cleaning)

38 pH Scale A measure of the H+ ion concentration in a solution. Each whole number change in PH value is a 10 fold d/f in H+ concentration pH Scale 0-14 <7 is acid =7 is neutral >7 is base The farther away from 7 the stronger the acid or base

39 pH Scale Click on the image to see an animation

40 Indicators and Buffers Indicators  Compounds which look different according to the pH  pH paper; litmus paper. Phenolphalein, bromthymol Blue.  All change color in response to pH Buffers Compounds which resist changes in PH serve as reservoir for H+ ions. Can donate or accept H+ ions Very important in maintaining homeostasis in living organisms

41 CHEMICAL REACTIONS Dehydration Synthesis  Synthesis: to make  A+B  C In the animation notice the water molecule bouncing away from the sucrose Click on the image to see an animation

42 CHEMICAL REACTIONS Hydrolysis to split apart using water The water wedges itself against the A-B bond until it breaks A B H2OH2O A B +

43 Metabolism We use both hydrolysis & dehydration synthesis Hydrolysis breaks down the food we eat. Dehydration synthesis builds what our bodies need

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