General Chemistry Questions & Answers

General Chemistry Questions & Answers 1 amu = - CORRECT ANSWER- 1 g/mol 1 Mole = _________ L - CORRECT ANSWER- 22.4 L 3.75 moles of nitrogen gas is held in a rubber balloon with a current volume of 1 L. The balloon is placed in a room with an initial pressure of 1 atm and temperature of 25°C. If the pressure suddenly drops to 0.75 atm, what change in volume is necessary if the temperature is to remain the same? - CORRECT ANSWER- The volume must be increased to 1.33 L. Correct Answer While we could plug all of the given values into the ideal gas law, we can make this problem much simpler by using Boyle's law, P1V1 = P2V2. Since initial pressure is 1 atm and initial volume is 1 L, we get (1 atm)(1 L) = (0.75 atm)(x L). The new volume must be approximately 1.33 L. A balloon is inflated until its volume reaches 2 L. Assuming all else is held constant, what would happen to the balloon's volume if it were moved to a colder environment? - CORRECT ANSWER- It would decrease. Correct Answer Charles' law states that as temperature increases, volume also increases. Therefore, if temperature decreases, the volume of the balloon should also decrease. A biologist is making a variety of measurements for a sample of CO2 generated by a colony of aerobic bacteria. The sample contains exactly 1 mole of gas and is being held in a 0.05 L container. When the biologist calculates the PV/ RT ratio of the gas, he finds that it is 1.05. How could this finding be explained? - CORRECT ANSWER- The high pressure in the flask is causing particle volume to exert a substantial effect. Correct Answer Since the sample contains 1 mole of gas, we can rearrange the ideal gas law to find our expected PV/RT ratio: 1. The given value is higher, implying that either pressure or volume is larger than expected. For the ideal gas law to work properly, two main assumptions are necessary: that the volume of particles themselves is negligible and that no intermolecular forces are present between particles. However, these assumptions become especially untrue at low temperature and high pressure. Classically, we think of low temperatures systems being significantly moved away from ideal gas behavior by intermolecular forces, and high pressure systems as being influenced primarily by intermolecular collisions. a electron close to nucleus - CORRECT ANSWER- stable and low energy A high Ea = - CORRECT ANSWER- Low rate constant A particular compound has the empirical formula C2H6ON. Which of the following options is closest to the percent composition by mass of nitrogen in this compound? - CORRECT ANSWER- 25% The molar ratio of this compound is 2:6:1:1. To determine the percent composition by mass, it is necessary to convert this mole ratio into a gram ratio. To do so, it's easiest to convert based on the number of moles in the empirical formula. Carbon's molar mass is 12 g/mol, so there are 24 g of carbon. Hydrogen's molar mass is 1 g/mol, so there are 6 g of hydrogen. Oxygen's molar mass is 16 g/mol, so there are 16 g of oxygen. Nitrogen's molar mass is 14 g/mol, so there are 14 g of nitrogen. There are 60 g in total, 14 g of which are nitrogen. Thus, the percent composition by mass of nitrogen in this compound is 14 g / 60 g = 0.23, or roughly 25%. A reaction is second order with regards to A and first order with regards to B