Chapter 3 notes.notebook - Mrs. Freeman's AP Chemistry

1 Chapter 3 06, 2016 Sep 22 1:45 PMChapter 3 stoichiometry Sep 22 1:45 PMStoichiometry Average atomic mass: The weighted average of all isotopes of a specific element. Takes into consideration abundance of each isotope. (% x M1) + (% x M2) +.. Chapter 3 06, 2016 Sep 22 1:45 PMCopper has two isotopes: of all copper has a mass of 63 amus and of all copper has a mass of 65 amus. What is copper's atomic mass?Notice which isotope the average atomic mass is closest to!!! stoichiometry Oct 1 3:41 PMMass Spectroscopy: A separation technique used to separate substances in a mixture based on their mass. stoichiometry Chapter 3 06, 2016 Oct 1 3:41 PMStoichiometry Oct 4 1:52 PMAvogadro's Number: particles in 1 mole(Sand is just SiO2)Molar Mass: The addition of the atomic mass of each atom (go out to the hundredth place!) stoichiometry Chapter 3 06, 2016 Oct 24 1:41 PMPercent composition: Compares the mass of one element in 1 mole of a compoundC2H5 OHStoichiometry Molar mass = g/mol2 carbons = 2 x = comp of comp = 100 = 24 2:06 PMCalculate the mass percent for all of the elements present in Penicillin F.

2 C14H20N2SO4 stoichiometry Chapter 3 06, 2016 Oct 24 2:14 PMEmpirical Formula: Chemical compound with the lowest whole number ratio. Molecular Formula: chemical compound with the same ratio as the empirical or a multiple of the empirical C3H8 , C6H16 C3H8 stoichiometry Oct 24 2:22 PMLet's say we know that a compound has the following Mass Cl , C , HStoichiometry Chapter 3 06, 2016 Oct 24 2:38 PMA white powder is analyzed and found to contain phosphorus and oxygen by mass. The compound has a molar mass of g/mole. what are the compound's empirical and molecular formulas? stoichiometry Oct 24 3:05 PMCaffeine contains carbon, hydrogen, nitrogen, and oxygen by mass and has a molar mass of g/mole. determine the molecular formula for caffeine. stoichiometry Chapter 3 06, 2016 Oct 29 8:12 AMRubbing alcohol was found to contain % carbon, % hydrogen.

3 What is the empirical formula of rubbing alcohol? A sample of indium chloride weighing g is found to contain g of chlorine. What is the empirical formula of the indium compound? stoichiometry Oct 29 8:13 AMAn unknown compound was found to have a percent composition as follows: % potassium, % carbon, and % oxygen. What is its empirical formula? If the true molar mass of the compound is g/mol, what is its molecular formula? stoichiometry Chapter 3 06, 2016 Oct 24 3:08 PMWhat mass of oxygen will react with grams of propane? C3H8 + O2 CO2 + H2O1. Balance the equation firstC3H8 + 5O2 3CO2 + 4H2O2. Convert the grams of propane into g C3H81 mol C3H8= mol C3H83. Convert the moles of Propane into moles oxygen = O21 mol mol g O24. Convert the moles of Oxygen into grams of oxygen 1 mol C3H8= mol mol C3H85 mol O2 stoichiometry Oct 24 3:28 PMSolid Lithium Hydroxide is used in space vehicles to remove exhaled carbon dioxide from the living environments by forming solid lithium carbonate and liquid water.

4 What mass of gaseous carbon dioxide can be absorbed by of lithium hydroxide? stoichiometry Chapter 3 06, 2016 Oct 24 3:32 PMBaking soda (sodium bicarbonate) is often used as an antacid. It neutralizes excess hydrochloric acid secreted by the stomach. Milk of Magnesia, which is an aqueous suspension of magnesium hydroxide, is also used as an antacid. Which is the more effective antacid per gram? stoichiometry Oct 24 3:35 PMLimiting Reactant: The reactant that is consumed first and that limits the amounts of products that can be formedNitrogen gas can be prepared by passing gaseous ammonia over solid copper (II) oxide at high temperatures. the other products of the reaction are solid copper and water vapor. If a sample containing of ammonia is reacted with g of CuO, which is the limiting reactant? How many grams of N2 will be formed. 2NH3 + 3 CuO N2 + 3Cu + 3H2O gStoichiometry Chapter 3 06, 2016 Oct 24 3:42 PM2NH3 + 3 CuO N2 + 3Cu + 3H2O NH31 mol NH32 mol NH31 mol N21 mol N2= CuO1 mol CuO3 mol CuO1 mol N21 mol N2= N2 Copper (II) oxide makes the smaller amount of Nitrogen, therefore copper (II) oxide is the limiting reagent and only of Nitrogen gas is made stoichiometry Oct 24 3:49 PMTheoretical yield: The amount of product formed when the limiting reactant is completely consumedPercent Yield: The actual yield of product divided by the theoretical yield times 100 stoichiometry Chapter 3 06, 2016 Oct 29 8:18 AMA g sample of Mg(OH)2 is reacted with g of HCl What is the theoretical yield of MgCl2?

5 Mg(OH)2 + 2 HCl > MgCl2 + 2 g Mg(OH)2 Mg(OH)21 mol Mg(OH)21 mol Mg(OH)21 mol MgCl21 mol g HCl g HCl1 mol HCl2 mol HCl1 mol MgCl21 mol MgCl282. 71g g MgCl2If only grams of MgCl2 is formed, what is the percent yield for this reaction? stoichiometry Sep 22 9:47 AMDilutions: Adding water to decrease concentrationM1V1 = M2V2 Concentration: A measurement of how much solute is dissolved in a specific solvent or solutionPercent by mass = Mass of the solutemass of the solutionx 100 Percent by volume = Volume of the soluteVolume of the solutionx 100 Molarity (M) =moles of soluteliters of solution Molality (m) =moles of solute kg solventStoichiometry Chapter 3 06, 2016 Sep 22 9:57 AMYou are combining grams of barium hydroxide with ml of M hydrofluoric acid, how much barium fluoride will be formed? What is the concentration of the other product.

6 stoichiometry Oct 1 3:39 PM