This Venn diagram is being used to compare primary and secondary successions. Which statement belongs in the region marked X? occurs only in cases of volcanic activity changes occur gradually begins when lichens populate an area results in a reduction of the number of species

How many moles are in 250 grams of tungsten (w)? * 4.4x10^23 moles 4.2x10^23 moles 0.7 moles 1.4 moles

If 90.0 grams of ethane reacted with excess chlorine, how many grams of dicarbon hexachloride would form

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.