Which of the following is true of elements?
OA. They are always composed of only two types of matter.
1.
B. They are composed of two or more types of matter.
c. They are not composed of any type of matter.
D.
They are composed of only one type of matter.

Describe the difference between a. a hypothesis and a theory and b. an observation and an experiment.

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.

What is the pressure of 0.500 moles of carbon dioxide gas in a 2.5 l tank and at a temperature of 301 k? (r=0.0821 l·atm/mol·k) 3.08 atm 1.2 atm 0.23 atm 4.01 atm 4.94 atm