An experiment applies heat to a substance and produces a gas that is a new and different substance. choose the true statement.
a. this represents a physical change only.
b. this represents a chemical change only.
c. this represents both a physical and a chemical change.
d. this represents neither a physical change nor a chemical change.

When determining the shape of a molecule, it is important to draw a lewis dot structure first in order to see the total number a. electrons within the moleculeb. bonding and unshared pairs around central atomc. unshared pair within the molecule( i really need it )

For the following dehydrohalogenation (e2) reaction, draw the zaitsev product(s) resulting from elimination involving c3–c4 (i.e., the carbon atoms depicted with stereobonds). show the product stereochemistry clearly. if there is more than one organic product, both products may be drawn in the same box. ignore elimination involving c3 or c4 and any carbon atom other than c4 or c3.

Astudent reacts 13 moles of iron with 21 moles of oxygen according to the following equation: