PPT-Empirical Formulas Knowing exactly what it is

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. 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 . 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. 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. 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. 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?. 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.. 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. General definitions. Mole. Homogeneous mixture. Heterogeneous mixture. Pure Substances. Compounds . Chemical Change . Chemical Property. Physical Change . Physical Property. Solid . Liquid . Gas. Evaporation. 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. ~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 .