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:
BASIC CHEMISTRY Unit 1
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.
Scientific Method This site has a nice explanation and a quiz for you to test yourself od.html od.html
States Of Matter Solid Definite shape and volume. Liquid Takes shape of container; definite volume. Gas Takes shape of container. (compressible).
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.
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
Energy Kinetic Energy The energy of motion Potential Energy Stored energy
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
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.
Periodic Table Another version at
Atomic Structure Atoms are electrically neutral Composed of protons, neutrons & electrons
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
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
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
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
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
Electron Arrangement For example: Cobalt (Co) Atomic Number 27, Atomic Mass ( 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
Electron Arrangement Now would be a good time for you to work on the Periodic Table Assignment!
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
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
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
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
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
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
Macromolecules: Proteins Protein Structure Click on the image to see an animation
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
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
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
Macromolecules: Nucleic Acids Information storage DNA: DeoxyriboNucleic Acid) Organism’s instructions for assembly Double stranded Located in nucleus BASES AdenineGuanine ThymineCytosine
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
Macromolecules: Lipids / Fats Insoluble in water. Combination of fatty acids and glycerol. Reserve energy storage. Make up cell membranes and some hormones
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
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
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)
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
pH Scale Click on the image to see an animation
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
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
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 +
Metabolism We use both hydrolysis & dehydration synthesis Hydrolysis breaks down the food we eat. Dehydration synthesis builds what our bodies need