Froggy Jumps Grade 10 Chemistry: Percent Composition & Empirical FormulasOnline version 60-second challenges on mass % and empirical formulas. by sameh Ali 1 A compound has 52 g C, 13 g H, and 26 g O. What is the percent composition of carbon? You have 60 seconds to answer. a 62.5% b 57.1% c 43.0% 2 A compound is 40% C, 6.7% H, and 53.3% O by mass. Its empirical formula is? You have 60 seconds to answer. a CH2O b C2H4O2 c CO2 3 A compound has empirical formula CH2O and molar mass 90 g/mol. What is its molecular formula? You have 60 seconds to answer. a C6H12O6 b C2H4O2 c C3H6O3 4 Percent composition of CO2 is approximately? You have 60 seconds to answer. a C: 40.0%, O: 60.0% b C: 27.3%, O: 72.7% c C: 60.0%, O: 40.0% 5 If a compound has 24.31 g Mg and 40.30 g O, the percent composition of Mg is? You have 60 seconds to answer. a 40.3% b 60.3% c 71.5% 6 An empirical formula from masses: 12 g C, 16 g O, 4 g H gives empirical formula? You have 60 seconds to answer. a CH2O b C2H4O2 c CH4O 7 Which of these represents a valid empirical formula from mass data? You have 60 seconds to answer. a NH b NHO2 c N2H2O 8 A compound with mass percent C 50%, H 6.7%, O 43.3%. Empirical formula is? You have 60 seconds to answer. a C2H5O b C3H6O3 c CH2O 9 Percent composition of iron oxide, Fe2O3: Fe ~70.9%, O ~29.1%. True or false? You have 60 seconds to answer. a True b False c Cannot determine
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