Which is the number of atoms in 4.5 moles of hg, correctly written in scientific notation with the correct number of significant figures? 2.7 x 10^24 27 x 10^23 2.71 x 10^24 27.099 x 10^23

6what is the importance of water on earth? a) it keeps the top layer of the geosphere cool b) it allows life to exist c) it provides ice at the poles d) it creates earth's blue color from space

How many mmols of tris-hcl are there in 100 ml of a 100 mm tris-hcl buffer solution at ph 8.1? note that the 100 mm refers to the sum of tris and tris-hcl concentrations?

Problem page combustion of hydrocarbons such as pentane ( c5 h12 ) produces carbon dioxide, a "greenhouse gas." greenhouse gases in the earth's atmosphere can trap the sun's heat, raising the average temperature of the earth. for this reason there has been a great deal of international discussion about whether to regulate the production of carbon dioxide.(a) write a balanced chemical equation, including physical state symbols, for the combustion of liquid pentane into gaseous carbon dioxide and gaseous water. (b) suppose 0.350 kg of pentane are burned in air at a pressure of exactly 1 atm and a temperature of 20.0 degree c. calculate the volume of carbon dioxide gas that is produced. be sure your answer has the correct number of significant digits.