Wei saw a special type of plastic that would melt and become a liquid when it was placed in the sun, but it would not melt when placed under a desk lamp. Why does light from the sun melt the plastic when light from the desk lamp does not?

Which of these properties, used alone, would be least useful in identifying most minerals? a. color b. luster c. streak d. density

Ageologist determines that a sample of a mineral can't be scratched by a steel nail but can be scratched by a masonry drill bit. based on this information, the sample mineral has to be softer than a. orthoclase. b. fluorite. c. apatite. d. corundum.

When balancing a chemical equation: