Which of the following observations would indicate that a material is a pure substance

What are the major products produced in the combustion of c10h22 under the following conditions? write balanced chemical equations for each. a. an excess of oxygen b. a slightly limited oxygen supply c. a very limited supply of oxygen d. the compound is burned in air

In which phase(s) do the molecules take the shape of the container?

Which fossil fuel is mainly used for heating and cooking? a. electricity b. coal c. petroleum d. natural gas