Acylinder contains 250 g of helium at 200 k. the external pressure is constant at 1 atm. the temperature of the system is raised by 74 k. calculate the heat lost or gained by the system. calculate your answer to three significant figures and express you answer in j. heat capacity for helium = 20.8 j/(mol k) molecular weight for helium = 4 g/mol

Which of the following statements is false regarding aromaticity? a. the compound must be cyclic b. the compound must be fully conjugated c. the compound must be planar d. the number of electrons in the pi system must satisfy the hückel 4n+2 rule e. the compound must have a neutral charge

Listen base your answer to the question on the information below. propane is a fuel that is sold in rigid, pressurized cylinders. most of the propane in a cylinder is liquid, with gas in the space above the liquid level. when propane is released from the cylinder, the propane leaves the cylinder as a gas. propane gas is used as a fuel by mixing it with oxygen in the air and igniting the mixture, as represented by the balanced equation below. c3h8(g) + 5o2(g) → 3co2(g) + 4h2o() + 2219.2 kja small amount of methanethiol, which has a distinct odor, is added to the propane to consumers detect a propane leak. in methanethiol, the odor is caused by the thiol functional group (–sh). methanethiol, ch3sh, has a structure that is very similar to the structure of methanol. what is the correct structural formula for a molecule of methanethiol

Indicate whether the specified alkyl halides will form primarily substitution products, only elimination products, both substitution and elimination products, or no products when they react with sodium methoxide. 1-bromobutane 1-bromo-2-methylpropane 2-bromobutane 2-bromo-2-methylpropane