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 . Chemical Formula Relationships. Number of Atoms in a Formula. In writing the formula of a substance, subscript numbers are used to indicate the number of atoms or groups of atoms of each element in the formula unit.. . vs. . Empirical Formula. Different compounds can have the . same. empirical formula. but . different. molecular formulas. .. Empirical . Formula is a . reduced. . form of Molecular formula . Molecular Formula and Empirical Formula. 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. 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. Chemistry GT 3/20/15. Drill. Calculate the percent composition of Na. 2. SO. 4. .. HW: Molecular Formula WS (pg. 4). MM. =142.05 . g. /mol. 32.37% Na, 22.58% S, 45.05% O. Chem. Joke of the Day. The photon checked into a hotel. What did it say when the bellhop asked for its bag?. Represents the . actual. number of . atoms. of each . element. in . compound. Not necessary for . ionic compounds. Necessary for . covalent compounds. The molecular formula for water is . H. 2. O. Formula from Exp. erimental D. at. a. Analysis of a Compounds Constituent Elements. The mass of elements that make up a compound can be used to determine the compounds chemical formula.. When determining a compounds empirical formula from mass data:. The Mole. Chemist’s counting number. amount. of a substance . 1 mole is equal to 6.022 x 10. 23. atoms or particles or molecules (Avogadro’s number). There are always 6.022 x 10. 23 . particles in . Empirical Formula . = . consists of the symbols for the elements combined in a compound, with subscripts . showing the smallest whole number ratio. Molar mass. = . the mass in grams of 1 mole of a substance. 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. Objectives:. -         . The student will determine an empirical, or simplest, formula from percentage composition data..  . PA Science and Technology Standards: 3.4.10.A; 3.4.12.A. PA Mathematics Standards: 2.2.11.A, 2.3.11.C, 2.4.11.E, 2.5.11.A. 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. Percent Composition. ~percent by mass of atoms present in a compound. = (mass of atom). . (total molar mass) x 100. water is . 88.81 . % Oxygen and . 11.19 . % Hydrogen. O- 16.00/18.016 x 100 = . 88.81 .