A 5.0 g sample of dry ice (solid carbon dioxide) turned into 2400 cm^3 of carbon dioxide gas at rtp. What was the
percentage purity of the dry ice? (Mr of CO2 = 44.)

List four observations that indicate that a chemical reaction may be taking place

Some liquids can be distilled, but only at temperatures that are so high that it is impractical, or so high the compound decomposes. explain why distillation such compounds at significantly less than atmospheric pressure (some degree of vacuum) would solve this problem.

When did stem cell research become known ? who discovered stem cell? what experiments or studies have been conducted so far?