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Empirical and Molecular Formulas. Drill. Create a Placemat on Your Giant Whiteboard…. Drill. What is the percent composition of Bromine in CuBr 2 ?. Agenda. Drill Review of HW Empirical/Molecular Formula Notes Case of the Chemical Culprit
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Drill Create a Placemat on Your Giant Whiteboard…
Drill • What is the percent composition of Brominein CuBr2?
Agenda • Drill • Review of HW • Empirical/Molecular Formula Notes • Case of the Chemical Culprit • Extra Practice (HW if not finished in class) • Looking Forward • CHECK FOR UNDERSTANDING ON PERCENT COMPOSITION AND EMPIRICAL FORMULA NEXT CLASS!!!!
Case of the Chemical Culprit • Ms. Fair’s room was left a mess the other day and found a mysterious substance on her desk. After watching the school’s cameras, she saw that there were 5 possible subjects and she examined their hands and found different substances on them. • She determined the mystery substance, but did not have time to determine what the substances were on the suspects.
Your Task • Use your notes to determine the empirical formula for the 5 different suspects • After calculating all results, see Ms. Fair’s results in the front of the room to determine who the culprit was!
HW • If you did not finish the additional practice, complete that for HW!!!
Looking Forward • Check for Understanding on Empirical Formula and Percent Composition • Possible Lab – Have to try it first
Empirical Formula • The lowest whole number ratio of atoms in a compound • Formulas for ionic compounds are ALWAYS empirical (lowest whole number ratio) • Examples: • NaCl • Al2(SO4)3 • MgCl2
Molecular Formula • The true number of atoms of each element in the formula of a compound • Example: • C2H8 • P4O10
Molecular and Empirical Formulas • Formulas for molecular compounds MIGHT be empirical (lowest whole number ratio)
Which of the following is NOT an empirical formula? • Na2SO4 • C6H5Cl • N2H4 • Sn3(PO4)4
Check for Understanding The lowest whole-number ratio of the elements in a compound is called? • Empirical formula • Molecular formula • Binary formula • Representative formula
Check for Understanding Which of the following compounds have the same empirical formula? • CO2 and SO2 • C7H14 and C10H20 • C4H10 and C10H4 • C6H12 and C5H14
Check for Understanding Which of the following is NOT true about empirical and molecular formulas? • The molecular formula of a compound can be the same as its empirical formula. • The molecular formula of a compound can be the same whole-number multiple of its empirical formula. • Several compounds can have the same empirical formula, but have different molecular formulas. • The empirical formula of a compound can be triple its molecular formula