Does anyone know these answers?

How did planetesmals form planets? a. they broke apart into smaller chunks. b. they collided and stuck together. c. they cooled and pulled ice together. d. they began to rotate.

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

Ammonium perchlorate nh4clo4 is the solid rocket fuel used by the u. s. space shuttle. it reacts with itself to produce nitrogen gas n2 , chlorine gas cl2 , oxygen gas o2 , water h2o , and a great deal of energy. what mass of nitrogen gas is produced by the reaction of 2.1g of ammonium perchlorate?