General Chemistry Questions & Answers

General Chemistry Questions & Answers A 20L sample at 300C and 5 atm of pressure contains 2 moles of a gas. If an additional 3 moles of gas at the same pressure and temperature are added, what is the final total volume of the gas? - CORRECT ANSWER - 50 L A container with 4 moles of a gas at a pressure of 6 atm has a volume of 12 liters. What is its temperature? (R=8.21E-2 L*atm/mol*K) - CORRECT ANSWER - 219K A mercury barometer is primarily affected by atmospheric pressure. What would happen to the level of mercury in the column if: a) the barometer was moved to the top of a mountain b) the barometer was placed ten meters under water - CORRECT ANSWER - a) the mercury level inside the thermometer would drop because the pressure opposing the force of the mercury would decrease b) the mercury level inside the thermometer would rise because the pressure opposing the force of the mercury would increase A person snaps an ice pack and pushes it onto their leg. In terms of energy transfer, what would be considered the system and what would be the surroundings in this scenario? - CORRECT ANSWER - System= ice pack surroundings= everything else A sample is assayed for lead by a redox reaction with I3- (aq). A 10g sample is crushed, dissolved in sulfuric acid, and passed over a reducing agent so that all the lead is in the form Pb2+. The Pb2+ (aq) is completely oxidized to Pb4+ by 32.60 mL of a .7M solution of NaI3. The balanced equation for the reaction is: I3- (aq) + Pb2+(aq) -- Pb4+(aq) + 3I- (aq) Calculate the mass of lead in the sample. - CORRECT ANSWER - 4.7g of lead in the sample A stock solution for making typical IV saline bags contains 90g of NaCl per 10 Liters of water (density = 1g/mL). What is the a) mole fraction and b) the percent composition by mass of NaCl in the saline solutions? - CORRECT ANSWER - a) 2.8E-3 b) 0.89% A vessel contains 8 mol O2, 3 mol CH4, and 1 mol CO2 at a total pressure of 240 atm. What is the partial pressure of each gas? - CORRECT ANSWER - O2 = .67 CH4 = .25 CO2 = .083 According to convention, what is written first- cation or anion? Based on this fact, what would be the oxidation state of the hydrogen ion in: