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CHEMISTRY SOL 4 REVIEW UNIT 9 – Molar Conversions Calculate the following: 2.11 x 1023 0.35 mol F = _________ atoms F 1.96 x 1024 3.25 moles CO2 = ________molecules 165.23 2.6 moles Cu = _______ g Cu 0.07 4.23 g NaCl = ________ moles NaCl 2009 SOL question The number of molecules in 48.0 g of oxygen gas (O2) is – A 6.02 x 1023 B 9.03 x 1023 C 1.20 x 1024 D 1.81 x 1024 UNIT 9 – Molar Conversions At STP, 1 mole of any gas occupies ______ Liters 22.4 What is the volume of 7.3 g of CO2 at STP? 3.72 L Find the density of O2 gas at STP. 1.43 g/L 2009 SOL question What is the volume occupied by 51 g of NH3 gas at STP? F 0.439 L G 22.8 L H 67.2 L J 91.9 L UNIT 10 - Stoichiometry What is the mole ratio of Al:Br in the following equation? 2Al (s) + 3Br2 (l) 2AlBr3 (s) 2:3 How many moles of O2 are produced when 2.35 moles of CO2 break down? CO2 C + O2 2.35 moles UNIT 10 - Stoichiometry LiOH + HBr LiBr + H2O If you start with 10 grams of lithium hydroxide, how many grams of lithium bromide will be produced? 36.25 g 2SO2 + O2 2SO3 What is the limiting reactant if you have 0.25 moles of each reactant? SO2 2009 SOL question If a student starts with 21.7 g of NH3, how many grams of hydrogen (H2) gas will be produced by the reaction? 2NH3 N2 + 3H2 3.85 g UNIT 10 - Stoichiometry LiOH + KCl LiCl + KOH I began this reaction with 20 grams of LiOH and produced 31 g of LiCl. What is my percent yield? Theoretical = 35.4 g Percent Yield = 87.6% UNIT 11 – Gas Laws Increasing the number of particles will ____________ the pressure of a gas. Increase Increasing volume will ________ the pressure of a gas. Decrease Decreasing the temperature will _______________ the pressure of a gas Decrease UNIT 11 – Gas Laws Draw a graph to show the relationship of volume and pressure. UNIT 11 – Gas Laws What’s the partial pressure of oxygen in a balloon filled with O2 and N2 if the total pressure in the balloon is 810 mmHg and the partial pressure of N2 is 610 mmHg? 200 mmHg UNIT 11 – Gas Laws When using any of the gas laws, what unit must you use for TEMPERATURE? Kelvin If we took 2.00 liters of a gas at 1.00 atm and compressed it to a pressure of 6.00 x 104 atm, what would the new volume of that gas be? P1V1 = P2V2 3.33 x 10-5 L UNIT 11 – Gas Laws If a balloon initially has a volume of 0.4 liters and a temperature of 20oC, what will the volume be after it is heated to a temperature of 250oC? V1/T1 = V2/T2 0.71 L UNIT 11 – Gas Laws If I have an unknown quantity of gas at a pressure of 1.2 atm, a volume of 31 liters, and a temperature of 87oC, how many moles of gas do I have? PV = nRT R = 0.0821 n = 1.26 moles UNIT 12 - Solutions What units do we use when measuring molarity (M)? moles/L How many moles of HCl are needed to make 675 mL of a 2.0 M solution? 1.35 moles UNIT 12 - Solutions In terms of solubility, polar substances tend to dissolve in _______________ substances. Other polar Why won’t oil and water stay mixed? Oil is nonpolar, water is polar List two ways you can speed the dissolving process. Stirring, Heating UNIT 12 - Solutions Which salt is most soluble at 10oC? KI How many grams of KCl can be dissolved in 200 g of water at 80oC? 100 g KCl UNIT 12 - Solutions Adding salt to ice or water alters it by _____________ the freezing point. Lowering/depressing 2.0 L of a 0.88 M solution is diluted to 3.8 L. What is the new molarity? M1V1 = M2V2 0.46 M UNIT 13 – Everything Else How is molar heat capacity different from specific heat capacity? Molar heat capacity talks about raising the temp of 1 mole, specific heat is 1 gram How many joules of heat are given off when 120 grams of water are cooled from 25oC to 10oC? The heat capacity of ice is 2.09 J/goC. Q = mc T Q = 3762 J UNIT 13 – Everything Else What kind of chemical would you use to neutralize an acid spill in a lab? Base (Ammonia, Sodium bicarbonate) What is the pH of a 0.1 M solution of a strong acid? 1 What is the pH of a 0.36 M solution of the strong base NaOH? 13.55 UNIT 13 – Everything Else What does pH measure? Concentration of hydrogen ions If a substance has a pH of 3, what is its pOH? 11