List the bonding pairs H and I; S and O; K and Br; Si and Cl, H and F; Se and S; C and H in order of increasing covalent character. 1. (S, O) < (Se, S) < (C, H) = (H, I) = (H, F) < (Si, Cl) < (K, Br) 2. (C, H) = (H, I) = (Se, S) < (K, Br) < (S, O) = (Si, Cl) < (H, F) 3. (K, Br) < (Si, Cl) < (H, F) = (H, I) = (C, H) < (Se, S) < (S, O) 4. (K, Br) < (H, F) < (Si, Cl) < (S, O) < (H, I) = (C, H) < (Se, S) 5. (Se, S) < (C, H) < (H, I) < (S, O) < (Si, Cl) = (H, F) < (K, Br) 6. (H, F) < (Si, Cl) = (S, O) < (K, Br) < (Se, S) = (H, I) = (C, H) 7. None of these

Problem #3 (ch. 1, problem 15)the ideal gas law provides one way to estimate the pressure exerted by a gas on a container. the law isí‘ťí‘ť=푛푛푛푛푛푛푉푉mo re accurate estimates can be made with the van der waals equationí‘ťí‘ť=í‘›í‘›í‘›í‘›í‘›í‘›í‘ ‰í‘‰â’푛푛푟푟â’푞푞푛푛2í‘ ‰í‘‰2where the term nb is a correction for the volume of the molecules and the term an2/v2is a correction for molecular attractions. the values of a and b depend on the type of gas. the gas constant is r, the absolutetemperature is t, the gas volume is v, and the number of moles of gas molecules is indicated by n. if n = 1 mol of an ideal gas were confined to a volume of v = 22.41 l at a temperature of 0â°c (273.2k), it would exert a pressure of 1 atm. in these units, r = 0.0826.for chlorine gas (cl2), a = 6.49 and b = 0.0562. compare the pressure estimates given by the ideal gas law and the van der waals equation for 1 mol of cl2 in 22.41 l at 273.2 k. what is the main cause of the difference in the two pressure estimates, the molecular volume or the molecular attractions?

The chart shows the bid provided by four contractors to complete a job. which contractor is the most cost-effective?

Nebulae are enormous clouds in outer space. they are made mostly of hydrogen gas, helium gas, and dust. some nebulae glow brightly, while others do not. the stars that people see are huge, bright balls of glowing gas. they are made mostly of hydrogen and helium. which statement correctly describes other ways in which nebulae and stars are different? a. stars can form inside a nebula but a nebula can never be produced by any star. b. a star always has a higher density than a nebula. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star.