scientific investigation starts with an observation of a natural phenomenon or problem, what observation prompted the family to conduct a scientific investigation? (please need help)

How to convert a density of 0.791g/cm3 to lb/ft3

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.

If 22.5 liters of oxygen reacted with excess of hydrogen, how many liters of water vapor could be produced?