Two changes are described below.

A green banana turns yellow and ripens.
A layer of rust forms on an iron nail.

Which statement is true about the two changes? (5 points)
Both are chemical changes because new substances are formed.
Both are physical changes because only the physical state of the substances change.
A is a physical change due to a change of state, but B is a chemical change because new molecules are formed.
A is a chemical change due to a change of state, but B is a physical change because new molecules are formed.

Fugu, also known as puffer fish, is a sushi delicacy that can also be lethal. puffer fish contain a powerful toxin that can kill an adult a few hours after ingestion. sushi chefs who prepare fugu must be specially trained because any contamination of the toxin-free areas of the fish can be deadly. recently this toxin has been put to good use, as scientists have discovered that a purified form of it can treat severe pain in cancer patients. this recent scientific discovery would fall under which area of chemistry? applied biochemistry pure organic chemistry pure physical chemistry applied inorganic chemistry

Which of the following is true for the actual yield of a reaction? it is always calculated as a ratio. it is the yield from the excess reactant. it is the yield from the limiting reactant. it is always less than the theoretical yield.

In the particles are arranged in a regular, repeating pattern. a)a crystalline liquid b)a crystalline solid c)all gases d)all solids