CH 101 1st Edition Lecture 2Outline of Last Lecture I. Basic Chemistry DefinitionsA. Converting from Grams to Moles and Grams to MoleculesII. Balancing Chemical EquationsIII. Finding the Molar Mass of a MoleculeIV. Introduction to StoichiometryA. Converting from Grams to MolesOutline of Current Lecture I. Converting from Grams to Moles to GramsA. The Difference between O and O2 II. How to Determine the Limiting Reagent in a Chemical ReactionA. The Drawing it Out MethodB. The Math MethodIII. The Scientific MethodA. Dalton’s Atomic TheoryIV. Defining Matter and EnergyCurrent LectureI. Converting from Grams to Moles to Grams- You will use stoichiometry to convert from grams to moles to grams when you are dealing with a compound such as Ca(NO3)2 and you have to find the mass of one of one of the elements that make up the compound. This form of stoichiometry is also used if you are given the mass of one of the elements or molecules that make up the compound and are asked to find the mass of the compound. When given a question like this, there are certain steps to follow. Step 1: Take the amount of grams given and convert it to moles by multiplying it by the ratio of moles to grams (1 mole / the atomic mass). Step two: Multiply by the ratio of moles of the substance that you know the mass of to the moles of the substance that you are trying to find the mass of. Step 3: multiply by the atomic mass of the substance that you are trying to find the mass of over I mole (atomic mass / 1 mole).Ex) A sample of Ca(NO3)2 contains 2.04 grams of Nitrogen. What is the mass of the Ca(NO3)2 sample?2.04 g N = 1 mole N / 14.007 g N Step 1 This step gives you the amount of moles in a 2.04 g sample of NitrogenThese 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.2.04 g N = 1 mole N / 14.007 g N = 1 mole Ca(NO3)2 / 2 moles N Step 2 This step give you the moles of Ca(NO3)2 in a 2.04 grams of Nitrogen. 2.04 g N = 1 mole N / 14.007 g N = 1 mole Ca(NO3)2 / 2 moles N = 164.086 g Ca(NO3)2 / 1 mole Ca(NO3)2 Step3 This step tells you the mass of Ca(NO3)2 that is produced from a 2.04 g sample of Nitrogen= 11.9 grams Ca(NO3)2  AnswerA. The Difference between O and O2 – Knowing the difference between when to use O and O2 isimportant because that’s the only way you can determine the correct molar ratios and properly balanceequations, O has 1 mole and O2 has 2 moles. O O is an atom, not an element or a moleculeHas a mass of 16. found on the Periodic TableOnly occurs after a chemical reaction that separates the two Oxygen atoms in O2O2O2 is an element and a moleculeHas a mass of 32 Is Oxygen’s natural state, Oxygen in the air is O2Ex) How many grams of oxygen does a 2.303 sample of Al2O3 contain? In this equation, the content tells us that oxygen means O not O2 because in the molecule Al2O3 contains 3 oxygen atoms which means O2 is slip apart to fulfill the 3 atoms needed to create Al2O3. Ex) How many grams of oxygen are required to react with 2.303 grams of Al to produce Al2O3? In this equation, the content tells us that oxygen means O2 because they are asking about oxygen reacting with Al. As a reactant, oxygen is in its natural state and therefore, is O2.II. How to Determine the Limiting Reagent in a Chemical Reaction-The limiting reagent is the reactant in a chemical reaction that produces the least product. You can findthe limiting reagent by drawing out the amount of moles of each reactant or by using an equation.A. The drawing it out method starts by finding the moles of each reactant and then drawing a circle to represent 1 mole for each reactant. To find the limiting reagent, you draw a circle around the atoms that form 1 mole of the product until you are left with not enough atoms to form the product. The atoms that are left are in excess and the atoms you have no more of is the limiting reactant. Ex) You are given 223.4 g of Fe and 354.5 g of Cl2 which react to produce the molecule Fe2Cl3. Find the limiting reagent and determine how many moles of the product are produced.4Fe(s) + 3Cl2(g)  2Fe2Cl3  First you ALWAYS have to balance your equation223.4 g Fe = 1 mole Fe / 55.85 g Fe = 4 moles Fe  Find the number of moles of each reactant by converting from grams to moles354.5 g Cl2 = 1 mole Cl2 / 70.906 g Fe = 5 moles Cl2  The large circles represent moles of Fe and the small red circles represent moles Cl2,each mole of Cl2 has 2 Cl atoms, therefore you draw a total of 8 Cl circles.  Group together the atoms the make up the product, in this case it’s Fe2Cl3 which contains 2 Fe atoms and 3 Cl atoms.  Answer, now you can see that you can produce 2 moles of Fe2Cl3 and that the limiting reagent is Cl2 which as 1 mole left overB. The Math Method starts the same way as the drawing it out method but instead of drawing out the moles of each reactant, you multiply the moles of each reactant by the ratio of moles of product over moles of reactant. The reactant with the smallest amount of product produced is the limiting reactant.Ex) You are given 223.4 g of Fe and 354.5 g of Cl2 which react to produce the molecule Fe2Cl3. Find the limiting reagent and determine how many moles of the product are produced.4Fe(s) + 3Cl2(g)  2Fe2Cl3  Balance equation223.4 g Fe = 1 mole Fe / 55.85 g Fe = 4 moles Fe  Find the number of moles of one of Fe4 moles Fe = 2 moles Fe2Cl3 / 4 moles Fe = 2 moles Fe2Cl3 Multiply by the ratio of moles of Fe2Cl3 to moles of Fe in order to find the amount of product produced354.5 g Cl2 = 1 mole Cl2 / 70.906 g Fe = 5 moles Cl2 Now find the moles of the other reactant, Cl5 moles Cl2 = 2 moles Fe2Cl3 / 3 moles Cl2 = 3.33 moles Fe2Cl3  Compare the moles of Fe2Cl3 produced by Cl2 tothe moles produced my Fe to determine that Fe is the limiting reagent. Since we know Fe is the limiting reagent, we also know that only 2 moles of Fe2Cl3 can be produced and that there will be approximately one mole of Cl2 left over because 3.33 – 2 = 1.33.III. The Scientific Method – A method used to study the sciences. The Phlogiston theory determined the law of conservation of matter using the scientific method. The scientific method is a process that starts with an observation, a hypothesis is …