PPT-Percent Composition and Empirical Formulas

Percent Composition percent by mass of atoms present in a compound mass of atom total molar mass x 100 water is 8881 Oxygen and 1119 Hydrogen O 160018016 x 100 8881 . Lesson 28. Warm up. Submit Mole Conversion packages in basket, and copy the following upon arrival. Write-Pair-Share. What is the percent of the total composition of each ingredient in the following recipe (masses are fictitious):. Week 22 Chemistry. Warm Up: . 3. Minutes. A certain bag of M&M’s has 8 blue candies, 7 red candies, 4 green candies, and 6 yellow candies. What percentage of the bag is blue M&M’s? . Record your Learning . 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. 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. . 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?. 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. . Percent Composition – . the percentage by mass of each element in a compound . Percent =. _______. Part. Whole. x 100%. So…. Percent composition. of a compound or =. molecule. Empirical & Molecular Formula Notes. Drill. Calculate the percent composition of Na. 2. SO. 4. .. HW:. Finish pg. 3 (Empirical Formulas). MM=142.05 . g. /mol. 32.37% Na, 22.58% S, 45.05% O. Objectives. Compounds are ALWAYS composed of elements in fixed ratios. This is often referred to as the . Law of Definite Proportions.. This law states that elements are always present in the same proportions by mass in a compound. I.e. H. 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 . 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.. Due at end of Period. The compound . benzamide. has the following percent composition. What is the empirical formula? . C . = 69.40 % H= 5.825 % O = 13.21 % N= 11.57 % . 2. A . component of protein called serine has an approximate . 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.