1 / 64

Basic CHEMISTRY

Learn about the smallest particles in chemistry, the atom, and its composition of protons, neutrons, and electrons. Explore chemical bonds, mixtures, compounds, and chemical reactions. Understand the concepts of acids, bases, and the pH scale.

joanel
Download Presentation

Basic CHEMISTRY

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Basic CHEMISTRY

  2. Smallest Particles • Elements: simplest form of a substance - cannot be broken down any further without changing what it is • Atom: the actual basic unit - composed of protons, neutrons, and electrons

  3. THE ATOM • Just like cells are the basic unit of life, the ATOM is the basic unit of matter. • They are very small. If placed side by side one million would stretch a distance of 1cm. • The atom is made up of 3 particles.

  4. Electrons are not present within the atom, instead THEY REVOLVE AROUND THE NUCELUS OF THE ATOM & FORM THE ELECTRON CLOUD • Draw a helium atom. Indicate where the protons, neutrons and electrons are. NEUTRONS PROTONS - ATOMIC # = 2 (PROTONS) ATOMIC MASS = 4 (PROTONS & NEUTRONS) + + ELECTRONS -

  5. ISOTOPES • atoms of the same element that HAVE A DIFFERENT NUMBER OF NEUTRONS • Some isotopes are radioactive. This means that their nuclei is unstable and will break down at a CONSTANT RATE over timecalled their half life • There are several practical uses for radioactive isotopes: • CARBON DATING • Kill CANCER CELLS

  6. COMPOUNDS • a substance formed by the chemical combination of 2 or more elements in definite proportions • Ex: water, salt, glucose, carbon dioxide H20 CO2 NaCl

  7. TWO TYPES OF COMPOUNDS • Organic - Contain C, H, and O in some ratio (usually referred to as chemicals of life) • Carbohydrates, Proteins, Lipids, Nucleic Acids • Inorganic - usually "support" life - no specific ratio of C, H, and O • Water (H2O), Carbon Dioxide (CO2)

  8. Water • Water is not organic (because it doesn’t contain carbon) • Water has special properties • Polarity – one end of water is more negative and the opposite end more positive • Cohesion – the polarity causes water molecules to stick together (negative is attracted to positive ends) ex. Meniscus, water “beading”

  9. CHEMICAL BONDS • Chemical bonds hold the atoms in a molecule together. • There are 2 types of chemical bonds IONIC and COVALENT

  10. IONIC BONDS • Occur when 1 or more electrons are TRANSFERRED from one atom to another. • When an atom loses an electron it is a POSITIVE charge. • When an atom gains an electron it is a NEGATIVE charge • These newly charged atoms are now called IONS • Example: NaCl (SALT)

  11. COVALENT BONDS • Occur when electrons are SHARED by atoms. • These new structures that result from covalent bonds are called MOLECULES • ** In general, the more chemical bonds a molecule has the more energy it contains SHARING IS CARING!

  12. MIXTURES • A mixture is a material composed of TWO OR MORE ELEMENTS OR COMPOUNDS THAT ARE PHYSICALLY MIXED • Ex: salt & pepper mixed, sugar and sand – can be easily separated

  13. SOLUTION Two parts: • SOLUTE – SUBSTANCE THAT IS BEING DISSOLVED (SUGAR / SALT) • SOLVENT - the substance in which the solute dissolves • WATER is the universal solvent • Materials that do not dissolve are known as SUSPENSIONS. • Blood is the most common example.

  14. FORMULA • The chemical symbols and numbers that make a compound ("recipe") • Structural Formula – Line drawings of the compound that shows the elements in proportion and how they are bonded • Molecular Formula – the ACTUAL formula for a compound C2H6O

  15. CHEMICAL REACTIONS • a process that changes one set of chemicals into another set of chemicals • REACTANTS – elements or compounds that enter into a chemical reaction • PRODUCTS – elements or compounds that are produced in a chemical reaction • catalyst: inorganic or organic substance which speeds up the rate of a chemical reaction without entering the reaction itself

  16. ACIDS & BASES • Acids: always (almost) begin with "H" because of the excess of H+ ions (hydrogen) • Ex: lemon juice (6), stomach acid (1.5), acid rain (4.5), normal rain (6) Facts about Acids • Acids turn litmus paper RED and usually taste SOUR. • You eat acids daily (coffee, vinegar, soda, spicy foods, etc…)

  17. ACIDS & BASES • Bases: always (almost) end with -OH because of the excess of hydroxide ions (Oxygen & Hydrogen) • EX: oven cleaner, bleach, ammonia, sea water, blood, pure water Facts about Bases • Bases turn litmus BLUE. • Bases usually feel SLIPPERY to touch and taste BITTER.

  18. pH SCALE 0--------------7---------------14 Acid Neutral Base • pH scale ranges from 0 -14 • pH 7 is neutral; neither acid nor base • Pure water is pH 7 • Low pH (0-6.9) = acid • High pH (7.1-14) = base • The closer to the ends of the scale, the stronger the solution is

  19. pH SCALE

  20. Why is pH important? Fish can’t live if the pH is too high or too low Soil has to be in a certain pH range for plants to grow and stay healthy.

  21. pH and People Water that has too high or low pH contains harmful dissolved chemicals. Water plant operators keep a careful watch on the pH of our drinking water, to keep it safe.

  22. x10 x100 Careful measurement is important A mistake of one pH unit means 10 times too much or too little! A Buffer is a weak acid or base that prevents sharp changes in pH.

  23. BIOCHEMISTRY

  24. 4 Organic Molecules Carbohydrates - Sugars (anything sweet), Grains (pasta, bread, rice, cereal, etc.) Lipids - Fats (oil, butter, grease, etc.) Proteins - Meats (fish, eggs, steak, beans, etc.) Nucleic Acids - DNA (found in every living cell)

  25. Indicators - Substances used to test the presence of a specific substance; Many times an indicator will change color when it combines with its specific molecule • Benedict’s Solution – turns from blue to yellow in the presence of glucose • Iodine – changes from amber to dark blue in the presence of starch • Paper Towel – turns shiny when a lipid is placed on its surface; ex. Fried foods leaving a grease spot • To find DNA we use many different indicators, such as luminol

  26. CARBOHYDRATES • Living things use carbohydrates as a key source of ENERGY! • Plants use carbohydrates for structure (CELLULOSE) • include sugars and complex carbohydrates (starches) • contain the elements C, H, and O (the hydrogen is in a 2:1 ratio to oxygen)

  27. Monosaccharides (simple sugars) • all have the formula C6 H12 O6 • all have a single ring structure • (glucose is an example)

  28. Disaccharides (double sugars) • all have the formula C12 H22 O11 • sucrose (table sugar) is an example

  29. Polysaccharides • Formed of three or more simple sugar units • Glycogen - animal starch stored in liver & muscles • Cellulose - indigestible in humans - forms cell walls • Starches - used as energy storage

  30. How are complex carbohydrates formed and broken down?

  31. Dehydration Synthesis • Combining simple molecules to form a more complex one with the removal of water • ex. monosaccharide + monosaccharide ----> disaccharide + water • (C6H12O6 + C6H12O6 ----> C12H22O11 + H2O • Polysaccharides are formed from repeated dehydration syntheses

  32. Hydrolysis • Addition of WATER to a compound to SPLIT it into smaller subunits • (also called chemical digestion) • ex. disaccharide + H2O ---> monosaccharide + monosaccharide

  33. Lipids (Fats) • Fats, oils, waxes, steroids • Chiefly function in energy storage, protection, and insulation • Contain C, H, and O but the H:O is not in a 2:1 ratio • Tend to be large molecules

  34. 3 fatty acids + glycerol ----> fat (lipid) - NOT a big long chain!!!! • Fats -- found chiefly in animals • Oils and waxes -- found chiefly in plants • Oils are liquid at room temperature, waxes are solids • Lipids along with proteins are key components of cell membranes (phospholipids) • Steroids are special lipids used for many reproductive hormones and cholesterol

  35. Fatty Acids can be • Saturated – all C-C single bonds • Liquid at room temp (oils) • Better to have in your diet • Unsaturated – at least one C=C (double bond) or a triple bond • Solid at room temp (fats) • Limit in diet – can lead to heart disease.

  36. PROTEINS • contain the elements C, H, N and O • composed of MANY amino acid subunits • It is the arrangement of the amino acids that forms the structure of proteins. • Structure determines the function

  37. AN R GROUP IS ANY GROUP OF ATOMS – THIS IS WHAT MAKES EACH AMINO ACID DIFFERENT AND CHANGES THE PROPERTIES OF THE PROTEIN! THERE ARE 20!!

  38. Major Protein Functions • Structure (you are MADE of protein) • Hormones • Antibodies • Growth and repair • ENZYMES (more to come) • Examples include insulin, hemoglobin, and skin.

  39. Dipeptide • formed by the process of Dehydration Synthesis • amino acid + amino acid ----- dipeptide + water

  40. Hydrolysis of a dipeptide • Breaking down of a dipeptide into amino acids • dipeptide + H2O ---> amino acid + amino acid

  41. Polypeptides Proteins are also called polypeptides They are made by putting together many amino acids in a chain The bond between the amino acids is called a peptide bond

  42. Enzymes and Enzyme Action • enzymes: organic catalysts made of protein • most enzyme names end in -ase • Written over the “arrow” in a reaction

  43. How do enzymes work? • substrate: molecules upon which an enzyme acts • the enzyme is shaped so that it can only lock up with a specific substrate molecule enzyme substrate -------------> product

  44. "Lock and Key Theory" • each enzyme is specific for one and ONLY one substrate (one lock - one key) • can “lock” and “unlock” • reuseable

  45. Factors Influencing Rate of Enzyme Action 1. pH - the optimum (best) in most living things is close to 7 (neutral) – water • high or low pH levels usually slow enzyme activity • A few enzymes (such as those in the stomach) work best at a pH of about 2.0

  46. 2. Temperature - strongly influences enzyme activity • optimum temperature for maximum enzyme function is usually about 37 C(body temp) • reactions proceed slowly below optimal temperatures • above 45 C most enzymes are denatured (change in their shape so the enzyme active site no longer fits with the substrate and the enzyme can't function) – like when you have a fever

More Related