General Chemistry Exam 2 with complete solution verified 100% correct How to find the mass of a molecule? - Answer - g molecule --> mol molecule --> Avogadro's #
Example:
(1 mol CO2 / 44.01g CO2) x (6.022 x 10^23 CO2 molecules / 1 mol CO2) OR (to organize the equation/steps) (44.01g CO2 / 1 mol CO2) x (1 mol CO2 / 6.022 x 10^23 CO2 molecules) Mass Percent Composition (Mass Percent) - Answer - (Mass of element X in 1 mol of compound / Mass of 1 mol of the compound) x 100%
Example: 1 / 3
(2 x molar mass Cl / molar mass CCl2F2) x 100% How to calculate the number of moles of each element that are present in each sample? - Answer -
Example:
0.857g H x (1 mol H / 1.01 g H) = 0.849 mol H 6.86g O x (1 mol O / 16.00g O) = 0.429 mol O [Divide each # of moles by fewest moles] 0.849 mol H / 0.429 = 1.98 => 2 0.429 mol O / 0.429 = 1 So, the empirical compound of Hydrogen and Oxygen is H2O How to calculate Molecular Mass [n] (After finding Empirical Formula and given Molar Mass in the problem)? - Answer - Molecular Mass [n] => (molar mass / empirical formula molar mass) Elemental Analysis - Answer - A method of obtaining Empirical Formulas for unknown compounds (containing C and H) by burning a sample of the compound in pure oxygen and analyzing the products of the combustion reaction.What must be in equilibrium in a "balanced" chemical reaction? - Answer - 1.) The number of atoms 2.) The amount of mass Organic Compounds - Answer - A compound composed of C and H and other elements: N, O, and S. 2 / 3
Example: Methane (CH4)
Hydrocarbons - Answer - Organic Compounds composed of only C and H.Alkanes, Alkenes, Alkynes (# of bonds)? - Answer - Alkanes => Hydrocarbons with single-bonded carbons Alkenes => Hydrocarbons with double-bonded carbons Alkynes => Hydrocarbons with triple-bonded carbons Base Names for Hydrocarbons - Answer - meth = 1 eth = 2 prop = 3 but = 4 pent = 5 hex = 6 hept = 7 oct = 8 non = 9 dec = 10 The Greenhouse Effect - Answer - Greenhouse gases in the atmosphere act as a one-way filter.They allow sunlight to pass through and warm Earth's surface.
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