PPT-The Mole Concept Molar Mass, Conversion Problems, Percentage Composition, Empirical Formulas,

The Mole Chemists counting number amount of a substance 1 mole is equal to 6022 x 10 23 atoms or particles or molecules Avogadros number There are always 6022 x 10 23 particles in . 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 . Calculate the following percentage by mass:. percent = portion/total x 100. If two samples are the same substance, they should have the . same percent composition by mass.. A compound will have the same physical and chemical characteristics.. Q: how long would it take to spend a mole of $1 coins if they were being spent at a rate of 1 billion per second?. Background: atomic masses. Look at the “atomic masses” on the periodic table. What do these represent?. 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?. 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. 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. Moles and Mass. The . molar mass . gives us the relationship between the . number of moles . and the . mass of an element or compound. .. We can . use the molar mass . to . calculate . the . mass. or . 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. First lesson of our next unit: U7 Stoichiometry . P3 Challenge – . Determine the number and kinds atoms for the chemical formula Al. 2. (SO. 4. ). 3. Today’s Objective –. Moles and particles. Assignment: . The amount of a substance that contains:. 6.02 x 10. 23 . particles (atoms, molecules, formula units). . 22.4 L (volume). X grams (molar mass). Put simply:. A mole is a unit of .