PPT-Empirical Formula Problems

Due at end of Period The compound benzamide has the following percent composition What is the empirical formula C 6940 H 5825 O 1321 N 1157 2 A component of protein called serine has an approximate . Molecular Formulas. Let’s use those mole conversions!. Empirical formula . tells you the lowest ratio of atoms within a molecule. Molecular formula . tells you the actual ratio of atoms within a molecule. Q- a compound is found to contain the following % by mass: 69.58% Ba, 6.090% C, 24.32% O. What is the simplest (i.e. empirical) formula?. Step 1. : imagine that you have 100 g of the substance. Thus, % will become mass in grams. E.g. 69.58 % Ba becomes 69.58 g Ba. (Some questions. You should know this for the quiz!. Empirical and Molecular Formulae. Empirical Formula. If needed, change % to g.. Do . a molar conversion to change from . g. mol. Divide each of these numbers by the smallest number. Do Now: from last years regents. Chemical Formulas. Tell . type. & . number. atoms in compound. Microscopic level: . Formula gives atom ratios. Macroscopic level: . Formula gives mole ratios. EXAMPLE. = based on data. . Usually % composition data. Why is it important to be able to calculate the empirical formula?. Penicillin . Antibiotic. Discovered about 80 years ago. Paved the way for other antibiotics to be created which increased life expectancy. Objectives. To learn how to work out the percentage composition by weight of a compound. To use percentage composition to work out empirical formulae. Percentage compositions. This means what percentage of each element is present in a compound, and therefore tells you what masses of each element are present in any given mass of a compound. . Molecular Formulas. Let’s use those mole conversions!. Empirical formula . tells you the lowest ratio of atoms within a molecule. Molecular formula . tells you the actual ratio of atoms within a molecule. Percent Composition, . Empirical/ Molecular . Formula . Finishing Up Ch. 10. In 1811, Avogadro proposed a hypothesis:. Volumes of gases at the same temp and pressure have the same number of particles. Seating Chart. Warm Up 1/5-6. Imagine your boss wants you to count the number of Styrofoam packing peanuts in a large bag. Suppose you found the mass of 100 peanuts to be 5.5 g. How could you use this to find the number of peanuts in the bag?. Percent Composition. Percent . Composition – . the . percentage . by mass of . each . element in a . compound (*note: not the ratio of elements in the compound). Law of Definite Proportions . – compounds always contain the same proportions of elements by mass.. Lowest whole # ratio . H. 2. O. 2. (hydrogen peroxide) is it a empirical Formula?. No, you can reduce it to HO . . H. 2. O. 2 . is the molecular formula. Molecular formula shows the way the molecule is actually found in nature.. Determining Molecular Formulas. Calculate the molecular formula of a compound whose molar mass is 60.0 g/mol and has an empirical formula of CH4N.. What you need:. Empirical Formula. Molar Mass. Calculate the molar mass of the empirical formula. Percent Composition. Breaks down the amount of an element in a compound by percentage. Total mass of element / total mass of compound. Result will always be a decimal. Multiply by 100 to get the final percentage. Introduction. How many jelly beans/pennies/peanuts/. etc. do you think is in this jar?. How can you make an educated guess and win these sort of contests?. Think of physical properties. Density. Volume.