The molar mass of this compound is 90.0 g/mol. Determine the molecular formula.

Which statement describes james chadwick’s discovery.

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.

Which organism develops breathing organism develops breathing organs from pharyngeal arches? shark, spider, sea star, sea horse