Go to the reagent bench and get a mortar and pestle. Place a small lump of sulfur in the mortar. Return to your bench and grind the sulfur to a powder. Pour the ground sulfur powder into the trash can. Wipe the sulfur off the mortar and pestle well with a paper towel and return them to the reagent bench. Observations:
Is this a chemical or a physical change?

Why is the bond angle in a water molecule less than the bond angle of methane? a. the central oxygen atom in water has two lone pairs of electrons, whereas the central carbon atom in methane has no lone pairs. b. the central hydrogen atom in water has one lone pair of electrons, whereas the central carbon atom in methane has two lone pairs. c. the central oxygen atom in water has four lone pairs of electrons, whereas the central carbon atom in methane has only one lone pair. d. the central oxygen atom exerts more repulsive force on surrounding atoms than the central carbon atom in methane does. reset next

Suppose the universe were completely empty except for one object-a solid sphere moving through space of 100 km/s. what sort of path would the object be moving in? explain your answer

How do dying stars contribute to the formation of planets