Which of these is true about pure substances?

A. They can only contain one type of atom

B. They can only contain one type of molecule

C. They may contain one type of atom or one type of molecule

D. They can contain different types of atoms and molecules

5th grade. Is air pressure higher in a vacuum or sea level

A car accelerates uniformly from + 10.0 m/s to + 40.0 m/s over a distance of 125 m. How long did it take to go that distance? Show all your work, including the equation used, given and unknown quantities, and any algebra required.

An eclipse of the moon is caused by the A. curvature of the moon. B. moon's shadow. C. curvature of the sun. D. Earth's shadow

Why is the overall charge on an atom neutral?

Why did the potassium permanganate crystals start to dissolve in water without being stirred or shaken

A geologist finds ripples preserved in ancient sedimentary rock that look just like ripples made by water in mud. He concludes that there was once water in that location that created the ripples. Why is this conclusion reasonable?

In science what is the requirement of doing work?

What Fitness Gram test is assessing your cardiovascular endurance?

A graph titled Position versus time for with horizontal axis time (seconds) and vertical axis position (meters). A straight blue line runs with an upward slope from 0 seconds 3 meters to 4 seconds 15 meters. The starting position of this object is m.

There is a 50 g sample of Ra-229. It has a half-life of 4 minutes. How much will be left after 12 minutes?