So i have no idea how to do this problem. Permanant hard watee contains calcium sulfate and can be softened by adding sodium carbonate. Determine the number of moles sodium carbonate needed to react 27.2 moles of calcium sulfate.
a. Write the chemical equation
b. Balance the chemical equation​

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.

Which are forms of frozen water? check all that apply. dew frost hail rain sleet

Why is retrograde motion an apparent motion