BIOLOGY 111 1st Edition Lecture 4 Outline of Last Lecture I. Continue Chemistry ReviewII. BondsIII. Chemical ReactionsIV. Properties of waterOutline of Current Lecture I. MolesII. MolarityIII. Acids and BasesIV. Organic ChemistryV. CarbonVI. IsomersCurrent LectureMoles- one mole is equal to 6.02 X 10^23 (Avogadro's number)For an Element: a mole is the atomic weight expressed in gramsFor a Compound: a mole is the formula (or molecular) weight in grams - this is a standardized ratio of the number of molecules/atoms per unit of weight that Represents an exact number of objects *standardized in the same form that a dozen is a dozen regardless of what (i.e. people, tables, chairs)*although 12 people are not equal in weight to 12 tables or 12 chairs, the moles of one substance doesn’t equal the moles of another substance in terms of weight (grams)!Conversion to and from moles:-given the grams of a substance and knowing molar mass, we can find the moles of a substance-with the moles of a substance, we use avogadro's number to find the number of atoms or molecules- this process can be done in the reverse order as well (knowing number of atoms/molecules to find grams of a substance)*the practical advantage of measuring a quantity of chemicals in moles is that a mole of one substance has exactly the same number of molecules as a mole of any other substance. It makesThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.it much more convenient for scientists working in a laboratory to combine substances in fixed ratios of moleculesEx. say you have 5.5 moles of water. To find the exact number of molecules, you would multiply 5.5moles by avogadro’s number. (5.5moles) X (6.02 X 10^23 molecules/moles) = 3.31 X 10^24 molecules of water Ex 2. Suppose you have 25 grams of water. You can find the number of moles (for a similar situation as the first example) by dividing the grams of water by the formula weight of the watercompound (weight of 2 hydrogens and 1 oxygen).(25 grams water) / (18.015 grams water) = 1.39 moles water *Know the molecular weight of hydrogen, carbon, oxygen and nitrogen for the test!Molarity- concentration is described as the number of moles of solute in a volume of solution [ Conc.= ( Mole / Liter ) ]- a solution has a concentration of 1 molar (1M) if there is 1 mole of substance in 1 Liter of solution*given glucose (180g) and 1 Liter of solution, how do you make .5M? and 1M glucose?o Since Concentration (.5M) = moles/Liter, and you want to find moles, you will multiply .5M by 1Liter to find discover there are .5 moles of glucose. To find grams we need to convert the .5 moles by multiplying it by molar mass(180g). So that (.5mol)X(180g)= 90 grams of glucose that was used.o do the same steps above to make 1M glucose. You should get 180 gramsof glucose. Water is composed of a ration between Hydrogen and Oxygen 2 grams of Hydrogen and 16 grams of Oxygen to equal roughly 18 grams of waterif the proportion is changed, you will not make the desired moleculefor example: 12 grams of Hydrogen and 4 grams of Oxygen will produce 18 grams but it will not be of water Occasionally, water molecules dissociate and the hydrogen bond between two water molecules shift and cause the hydrogen atom to transfer, with the product temporarily existing as:Hydrogen ions – a single proton with a charge of 1+ (H+)… this will never exist on its own it will be represented as a hydronium ionHydronium ions - where there is an extra H on the water (H2O) molecule making (H3O+) due these are acidic) and also have a charge of 1+Hydroxide ions - where there is one less H on the water (H2O) molecule making it (OH-)... (theseare basic) and have a charge of 1-*H+ and OH- are very reactive and play a huge role Acid vs Base- Acids – a substance that increases the hydrogen ion concentration of a solution(donate their extra H+ in aqueous solution)- Bases – a substance that reduces the hydrogen ion concentration of a solution[accept the H+ (sometimes they donate themselves as OH-) in aqueous solution]*[ ] = concentrationAcidic [H+] > [OH-] pH between 0-7Neutral [H+] = [OH-] pH around 7Basic [H+] < [OH-] pH between 7-14pH affects many things including...- shapes and functions of molecules- rates of chemical reactions- molecules ability to bind to each other- ions ability to dissolve in waterpH = -log( [H+'s concentration] )if [H+] concentration is 10^-5, then -log(10^-5) will give you the pH value of 5if pH is 5, then the [H+] value is 10^-5 M and the [OH-] value 10^-9 M- Increasing Hydrogen will increase acidity- Increasing Hydroxide will increase basicity (decrease acidity) Buffers – a substance that minimizes changes in the concentration of H+ or OH- in solution- weak acids or weak bases that help solutions resist changes in pH*this is important to prevent even the slightest deviation in our blood, which could be lethal◦ strong acids dissociate easily but hard to come back together◦ weak acids don't dissociate easily but if they do can come back together easily*to rise in pH will donate a proton (hydrogen) called a proton donor*to drop in pH will accept a proton (hydrogen) called a proton acceptorFor every change in pH by one unit, the acidity changes by 10XEx.pH around 7.4 is dropped to 6.4. the 1 pH difference represents 10 times as many H+ ionsEx 2. pH of 3 and pH of 6 differ in acidity by a thousand (10 X 10 X 10) AcidificationOcean acidification – When CO2 from the air dissolves in seawater, it reacts to form carbonic acid, which lowers ocean pH. As seawater acidifies, the extra hydrogen ions combine withcarbonate ions to form bicarbonate ions, reducing carbonate concentration.Acid precipitation – rain, snow, or fog with pH lower (more acidic) than 5.2.Chapter 4Organic Chemistry- study of molecules and compounds containing carbon (abundant in all living things)- Urea is one of the most abundant b/c discreted waste by living organisms Miller - Urey experiment◦ stimulated real atmosphere through a laboratory apparatus where they found the first few organic moleculesCARBON- can make 4 bonds with 4 valence electrons allowing formation of complex molecules (usually single or double bonds)- can form non-polar (poorly water soluble) and polar bonds (more water soluble)- simplest being hydrocarbons (hydrogen + carbon)o ex. CH4 C2H6 o hydrocarbons can